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Zhang P, Li Q, Li Z, Shi X, Wang H, Huo C, Zhou L, Kuang X, Lin K, Cao Y, Deng J, Yu C, Chen X, Miao J, Xing X. Intrinsic-strain-induced ferroelectric order and ultrafine nanodomains in SrTiO 3. Proc Natl Acad Sci U S A 2024; 121:e2400568121. [PMID: 38857392 DOI: 10.1073/pnas.2400568121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2024] [Accepted: 04/27/2024] [Indexed: 06/12/2024] Open
Abstract
Nano ferroelectrics holds the potential application promise in information storage, electro-mechanical transformation, and novel catalysts but encounters a huge challenge of size limitation and manufacture complexity on the creation of long-range ferroelectric ordering. Herein, as an incipient ferroelectric, nanosized SrTiO3 was indued with polarized ordering at room temperature from the nonpolar cubic structure, driven by the intrinsic three-dimensional (3D) tensile strain. The ferroelectric behavior can be confirmed by piezoelectric force microscopy and the ferroelectric TO1 soft mode was verified with the temperature stability to 500 K. Its structural origin comes from the off-center shift of Ti atom to oxygen octahedron and forms the ultrafine head-to-tail connected 90° nanodomains about 2 to 3 nm, resulting in an overall spontaneous polarization toward the short edges of nanoparticles. According to the density functional theory calculations and phase-field simulations, the 3D strain-related dipole displacement transformed from [001] to [111] and segmentation effect on the ferroelectric domain were further proved. The topological ferroelectric order induced by intrinsic 3D tensile strain shows a unique approach to get over the nanosized limitation in nanodevices and construct the strong strain-polarization coupling, paving the way for the design of high-performance and free-assembled ferroelectric devices.
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Affiliation(s)
- Peixi Zhang
- Beijing Advanced Innovation Center for Materials Genome Engineering, Institute of Solid State Chemistry, University of Science and Technology Beijing, Beijing 100083, China
| | - Qiang Li
- Beijing Advanced Innovation Center for Materials Genome Engineering, Institute of Solid State Chemistry, University of Science and Technology Beijing, Beijing 100083, China
| | - Zhiguo Li
- Beijing Advanced Innovation Center for Materials Genome Engineering, Institute of Solid State Chemistry, University of Science and Technology Beijing, Beijing 100083, China
| | - Xiaoming Shi
- Department of Physics, University of Science and Technology Beijing, Beijing 100083, China
| | - Haoyu Wang
- Department of Physics, University of Science and Technology Beijing, Beijing 100083, China
| | - Chuanrui Huo
- Beijing Advanced Innovation Center for Materials Genome Engineering, Department of Physical Chemistry, University of Science and Technology Beijing, Beijing 100083, China
| | - Lihui Zhou
- Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering, Feringa Nobel Prize Scientist Joint Research Center, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Xiaojun Kuang
- Guangxi Key Laboratory of Electrochemical and Magnetochemical Functional Materials, College of Chemistry and Bioengineering, Guilin University of Technology, Guilin 541006, China
| | - Kun Lin
- Beijing Advanced Innovation Center for Materials Genome Engineering, Institute of Solid State Chemistry, University of Science and Technology Beijing, Beijing 100083, China
| | - Yili Cao
- Beijing Advanced Innovation Center for Materials Genome Engineering, Institute of Solid State Chemistry, University of Science and Technology Beijing, Beijing 100083, China
| | - Jinxia Deng
- Beijing Advanced Innovation Center for Materials Genome Engineering, Institute of Solid State Chemistry, University of Science and Technology Beijing, Beijing 100083, China
| | - Chengyi Yu
- Beijing Advanced Innovation Center for Materials Genome Engineering, Institute of Solid State Chemistry, University of Science and Technology Beijing, Beijing 100083, China
| | - Xin Chen
- Beijing Advanced Innovation Center for Materials Genome Engineering, Institute of Solid State Chemistry, University of Science and Technology Beijing, Beijing 100083, China
| | - Jun Miao
- Beijing Advanced Innovation Center for Materials Genome Engineering, Institute of Solid State Chemistry, University of Science and Technology Beijing, Beijing 100083, China
| | - Xianran Xing
- Beijing Advanced Innovation Center for Materials Genome Engineering, Institute of Solid State Chemistry, University of Science and Technology Beijing, Beijing 100083, China
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2
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Li T, Deng S, Liu H, Chen J. Insights into Strain Engineering: From Ferroelectrics to Related Functional Materials and Beyond. Chem Rev 2024; 124:7045-7105. [PMID: 38754042 DOI: 10.1021/acs.chemrev.3c00767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2024]
Abstract
Ferroelectrics have become indispensable components in various application fields, including information processing, energy harvesting, and electromechanical conversion, owing to their unique ability to exhibit electrically or mechanically switchable polarization. The distinct polar noncentrosymmetric lattices of ferroelectrics make them highly responsive to specific crystal structures. Even slight changes in the lattice can alter the polarization configuration and response to external fields. In this regard, strain engineering has emerged as a prevalent regulation approach that not only offers a versatile platform for structural and performance optimization within ferroelectrics but also unlocks boundless potential in various functional materials. In this review, we systematically summarize the breakthroughs in ferroelectric-based functional materials achieved through strain engineering and progress in method development. We cover research activities ranging from fundamental attributes to wide-ranging applications and novel functionalities ranging from electromechanical transformation in sensors and actuators to tunable dielectric materials and information technologies, such as transistors and nonvolatile memories. Building upon these achievements, we also explore the endeavors to uncover the unprecedented properties through strain engineering in related chemical functionalities, such as ferromagnetism, multiferroicity, and photoelectricity. Finally, through discussions on the prospects and challenges associated with strain engineering in the materials, this review aims to stimulate the development of new methods for strain regulation and performance boosting in functional materials, transcending the boundaries of ferroelectrics.
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Affiliation(s)
- Tianyu Li
- Department of Physical Chemistry, University of Science and Technology Beijing, Beijing 100083, China
- Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Shiqing Deng
- Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Hui Liu
- Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Jun Chen
- Department of Physical Chemistry, University of Science and Technology Beijing, Beijing 100083, China
- Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing 100083, China
- Hainan University, Haikou 570228, China
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3
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Sha TT, Zhang XC, Zhou RJ, Du GW, Xiong YA, Pan Q, Yao J, Feng ZJ, Gao XS, You YM. Organic-Inorganic Hybrid Perovskite Ferroelectric Nanosheets Synthesized by a Room-Temperature Antisolvent Method. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2400636. [PMID: 38778554 DOI: 10.1002/advs.202400636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 04/17/2024] [Indexed: 05/25/2024]
Abstract
Over the past years, the application potential of ferroelectric nanomaterials with unique physical properties for modern electronics is highlighted to a large extent. However, it is relatively challenging to fabricate inorganic ferroelectric nanomaterials, which is a process depending on a vacuum atmosphere at high temperatures. As significant complements to inorganic ferroelectric nanomaterials, the nanomaterials of molecular ferroelectrics are rarely reported. Here a low-cost room-temperature antisolvent method is used to synthesize free-standing 2D organic-inorganic hybrid perovskite (OIHP) ferroelectric nanosheets (NSs), that is, (CHA)2PbBr4 NSs (CHA = cyclohexylammonium), with an average lateral size of 357.59 nm and a thickness ranging from 10 to 70 nm. This method shows high repeatability and produces NSs with excellent crystallinity. Moreover, ferroelectric domains in single NSs can be clearly visualized and manipulated using piezoresponse force microscopy (PFM). The domain switching and PFM-switching spectroscopy indicate the robust in-plane ferroelectricity of the NSs. This work not only introduces a feasible, low-cost, and scalable method for preparing molecular ferroelectric NSs but also promotes the research on molecular ferroelectric nanomaterials.
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Affiliation(s)
- Tai-Ting Sha
- Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing, 211189, P. R. China
| | - Xing-Chen Zhang
- Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials and Institute for Advanced Materials, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, 510006, P. R. China
| | - Ru-Jie Zhou
- Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing, 211189, P. R. China
| | - Guo-Wei Du
- Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing, 211189, P. R. China
| | - Yu-An Xiong
- Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing, 211189, P. R. China
| | - Qiang Pan
- Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing, 211189, P. R. China
| | - Jie Yao
- Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing, 211189, P. R. China
| | - Zi-Jie Feng
- Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing, 211189, P. R. China
| | - Xing-Sen Gao
- Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials and Institute for Advanced Materials, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, 510006, P. R. China
| | - Yu-Meng You
- Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing, 211189, P. R. China
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4
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Lafuente-Bartolome J, Lian C, Giustino F. Topological polarons in halide perovskites. Proc Natl Acad Sci U S A 2024; 121:e2318151121. [PMID: 38758696 PMCID: PMC11127022 DOI: 10.1073/pnas.2318151121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 03/29/2024] [Indexed: 05/19/2024] Open
Abstract
Halide perovskites emerged as a revolutionary family of high-quality semiconductors for solar energy harvesting and energy-efficient lighting. There is mounting evidence that the exceptional optoelectronic properties of these materials could stem from unconventional electron-phonon couplings, and it has been suggested that the formation of polarons and self-trapped excitons could be key to understanding such properties. By performing first-principles simulations across the length scales, here we show that halide perovskites harbor a uniquely rich variety of polaronic species, including small polarons, large polarons, and charge density waves, and we explain a variety of experimental observations. We find that these emergent quasiparticles support topologically nontrivial phonon fields with quantized topological charge, making them nonmagnetic analog of the helical Bloch points found in magnetic skyrmion lattices.
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Affiliation(s)
- Jon Lafuente-Bartolome
- Oden Institute for Computational Engineering and Sciences, The University of Texas at Austin, Austin, TX78712
- Department of Physics, The University of Texas at Austin, Austin, TX78712
| | - Chao Lian
- Oden Institute for Computational Engineering and Sciences, The University of Texas at Austin, Austin, TX78712
- Department of Physics, The University of Texas at Austin, Austin, TX78712
| | - Feliciano Giustino
- Oden Institute for Computational Engineering and Sciences, The University of Texas at Austin, Austin, TX78712
- Department of Physics, The University of Texas at Austin, Austin, TX78712
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5
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Wang Z, Chen LQ. Tuning Topology Phases by Controlling Effective Screening and Depolarization in Oxide Superlattices. NANO LETTERS 2024; 24:5761-5766. [PMID: 38709952 DOI: 10.1021/acs.nanolett.4c00858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Polar topological phases in oxide superlattices attracted significant attention due to their unique properties. Previous work revealed that a polar vortex and polar skyrmions exist in (PTO)/(STO) superlattices under different elastic constraints, i.e., on different substrates. Here, our phase-field simulation demonstrates that manipulating the PTO and STO layers' thickness can control the effective screening provided by STO and the depolarization degree in PTO, thus switching the system among the polar skyrmions, vortex labyrinth, or paraelectric phase without changing elastic constraints. Additionally, reducing the STO thickness creates interlayer coupling among PTO layers, generating the long-range order of topological phases within superlattices. Furthermore, we construct a PTO-STO thickness topological phase diagram. These findings offer insights into the polar topological phases' formation in oxide superlattices, elucidating the roles of ferroelectric and paraelectric layers in their formation.
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Affiliation(s)
- Zhiyang Wang
- Department of Materials Science and Engineering, Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Long-Qing Chen
- Department of Materials Science and Engineering, Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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6
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Wang YJ, Feng YP, Tang YL, Zhu YL, Cao Y, Zou MJ, Geng WR, Ma XL. Polar Bloch points in strained ferroelectric films. Nat Commun 2024; 15:3949. [PMID: 38729934 PMCID: PMC11087520 DOI: 10.1038/s41467-024-48216-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 04/24/2024] [Indexed: 05/12/2024] Open
Abstract
Topological domain structures have drawn great attention as they have potential applications in future electronic devices. As an important concept linking the quantum and classical magnetism, a magnetic Bloch point, predicted in 1960s but not observed directly so far, is a singular point around which magnetization vectors orient to nearly all directions. Here we show polar Bloch points in tensile-strained ultrathin ferroelectric PbTiO3 films, which are alternatively visualized by phase-field simulations and aberration-corrected scanning transmission electron microscopic imaging. The phase-field simulations indicate local steady-state negative capacitance around the Bloch points. The observation of polar Bloch points and their emergent properties consequently implies novel applications in future integrated circuits and low power electronic devices.
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Affiliation(s)
- Yu-Jia Wang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, 110016, Shenyang, China
| | - Yan-Peng Feng
- Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan, 523808, Guangdong, China
- Quantum Science Center of Guangdong-HongKong-Macau Greater Bay Area, Shenzhen, China
| | - Yun-Long Tang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, 110016, Shenyang, China
| | - Yin-Lian Zhu
- Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan, 523808, Guangdong, China
- Quantum Science Center of Guangdong-HongKong-Macau Greater Bay Area, Shenzhen, China
- School of Materials Science and Engineering, Hunan University of Science and Technology, Xiangtan, 411201, China
| | - Yi Cao
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, 110016, Shenyang, China
- School of Materials Science and Engineering, University of Science and Technology of China, Wenhua Road 72, Shenyang, 110016, China
| | - Min-Jie Zou
- Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan, 523808, Guangdong, China
- Quantum Science Center of Guangdong-HongKong-Macau Greater Bay Area, Shenzhen, China
| | - Wan-Rong Geng
- Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan, 523808, Guangdong, China
- Quantum Science Center of Guangdong-HongKong-Macau Greater Bay Area, Shenzhen, China
| | - Xiu-Liang Ma
- Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan, 523808, Guangdong, China.
- Quantum Science Center of Guangdong-HongKong-Macau Greater Bay Area, Shenzhen, China.
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
- State Key Lab of Advanced Processing and Recycling on Non-ferrous Metals, Lanzhou University of Technology, 730050, Lanzhou, China.
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7
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Jeong C, Lee J, Jo H, Oh J, Baik H, Go KJ, Son J, Choi SY, Prosandeev S, Bellaiche L, Yang Y. Revealing the three-dimensional arrangement of polar topology in nanoparticles. Nat Commun 2024; 15:3887. [PMID: 38719801 PMCID: PMC11078976 DOI: 10.1038/s41467-024-48082-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Accepted: 04/16/2024] [Indexed: 05/12/2024] Open
Abstract
In the early 2000s, low dimensional ferroelectric systems were predicted to have topologically nontrivial polar structures, such as vortices or skyrmions, depending on mechanical or electrical boundary conditions. A few variants of these structures have been experimentally observed in thin film model systems, where they are engineered by balancing electrostatic charge and elastic distortion energies. However, the measurement and classification of topological textures for general ferroelectric nanostructures have remained elusive, as it requires mapping the local polarization at the atomic scale in three dimensions. Here we unveil topological polar structures in ferroelectric BaTiO3 nanoparticles via atomic electron tomography, which enables us to reconstruct the full three-dimensional arrangement of cation atoms at an individual atom level. Our three-dimensional polarization maps reveal clear topological orderings, along with evidence of size-dependent topological transitions from a single vortex structure to multiple vortices, consistent with theoretical predictions. The discovery of the predicted topological polar ordering in nanoscale ferroelectrics, independent of epitaxial strain, widens the research perspective and offers potential for practical applications utilizing contact-free switchable toroidal moments.
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Affiliation(s)
- Chaehwa Jeong
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Juhyeok Lee
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
- Energy Geosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Hyesung Jo
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Jaewhan Oh
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Hionsuck Baik
- Korea Basic Science Institute (KBSI), Seoul, 02841, Republic of Korea
| | - Kyoung-June Go
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Junwoo Son
- Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Seoul, 08826, Republic of Korea
| | - Si-Young Choi
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
- Center for Van der Waals Quantum Solids, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
| | - Sergey Prosandeev
- Smart Ferroic Materials Center (SFMC), Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, AR, 72701, USA
| | - Laurent Bellaiche
- Smart Ferroic Materials Center (SFMC), Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, AR, 72701, USA
| | - Yongsoo Yang
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.
- Graduate School of Semiconductor Technology, School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.
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8
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Wang J, Liu Z, Wang Q, Nie F, Chen Y, Tian G, Fang H, He B, Guo J, Zheng L, Li C, Lü W, Yan S. Ultralow Strain-Induced Emergent Polarization Structures in a Flexible Freestanding BaTiO 3 Membrane. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2401657. [PMID: 38647365 DOI: 10.1002/advs.202401657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Indexed: 04/25/2024]
Abstract
The engineering of ferroic orders, which involves the evolution of atomic structure and local ferroic configuration in the development of next-generation electronic devices. Until now, diverse polarization structures and topological domains are obtained in ferroelectric thin films or heterostructures, and the polarization switching and subsequent domain nucleation are found to be more conducive to building energy-efficient and multifunctional polarization structures. In this work, a continuous and periodic strain in a flexible freestanding BaTiO3 membrane to achieve a zigzag morphology is introduced. The polar head/tail boundaries and vortex/anti-vortex domains are constructed by a compressive strain as low as ≈0.5%, which is extremely lower than that used in epitaxial rigid ferroelectrics. Overall, this study c efficient polarization structures, which is of both theoretical value and practical significance for the development of next-generation flexible multifunctional devices.
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Affiliation(s)
- Jie Wang
- Spintronics Institute, School of Physics and Technology, University of Jinan, Jinan, 250022, China
- Functional Materials and Acousto-Optic Instruments Institute, School of Instrumentation Science and Engineering, Harbin Institute of Technology, Harbin, 150080, China
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, China
| | - Zhen Liu
- School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China
| | - Qixiang Wang
- Spintronics Institute, School of Physics and Technology, University of Jinan, Jinan, 250022, China
| | - Fang Nie
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, China
| | - Yanan Chen
- Spintronics Institute, School of Physics and Technology, University of Jinan, Jinan, 250022, China
| | - Gang Tian
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, China
| | - Hong Fang
- Spintronics Institute, School of Physics and Technology, University of Jinan, Jinan, 250022, China
- Functional Materials and Acousto-Optic Instruments Institute, School of Instrumentation Science and Engineering, Harbin Institute of Technology, Harbin, 150080, China
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, China
| | - Bin He
- Spintronics Institute, School of Physics and Technology, University of Jinan, Jinan, 250022, China
| | - Jinrui Guo
- Spintronics Institute, School of Physics and Technology, University of Jinan, Jinan, 250022, China
| | - Limei Zheng
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, China
| | - Changjian Li
- Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
- Guangdong Provincial Key Laboratory of Functional Oxide Materials and Devices, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Weiming Lü
- Spintronics Institute, School of Physics and Technology, University of Jinan, Jinan, 250022, China
- Functional Materials and Acousto-Optic Instruments Institute, School of Instrumentation Science and Engineering, Harbin Institute of Technology, Harbin, 150080, China
| | - Shishen Yan
- Spintronics Institute, School of Physics and Technology, University of Jinan, Jinan, 250022, China
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, China
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9
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Minami S, Ikeda Y, Shimada T. Spontaneous Atomic-Scale Polar Skyrmions and Merons on a SrTiO 3 (001) Surface: Defect Engineering for Emerging Topological Orders. NANO LETTERS 2024; 24:3686-3693. [PMID: 38451549 DOI: 10.1021/acs.nanolett.3c05112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/08/2024]
Abstract
The emergence of nontrivial topological order in condensed matter has been attracting a great deal of attention owing to its promising technological applications in novel functional nanodevices. In ferroelectrics, the realization of polar topological order at an ultimately small scale is extremely challenging due to the lack of chiral interaction and the critical size of the ferroelectricity. Here, we break through these limitations and demonstrate that the ultimate atomic-scale polar skyrmion and meron (∼2 nm) can be induced by engineering oxygen vacancies on the SrTiO3 (001) surface based on first-principles calculations. The paraelectric-to-antiferrodistortive phase transition leads to a novel topological transition from skyrmion to meron, indicating phase-topology correlations. We also discuss accumulating and driving polar skyrmions based on the oxygen divacancy model; these results and the recent discovery of defect engineering techniques suggest the possibility of arithmetic operations on topological numbers through the natural self-organization and diffusion features of oxygen vacancies.
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Affiliation(s)
- Susumu Minami
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
| | - Yoshitaka Ikeda
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
| | - Takahiro Shimada
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
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10
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Shang H, Dong H, Wu Y, Deng F, Liang X, Hu S, Shen S. Mechanical Control of Polar Patterns in Wrinkled Thin Films via Flexoelectricity. PHYSICAL REVIEW LETTERS 2024; 132:116201. [PMID: 38563913 DOI: 10.1103/physrevlett.132.116201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 11/17/2023] [Accepted: 02/09/2024] [Indexed: 04/04/2024]
Abstract
Intriguing topological polar structures in oxide nanofilms have drawn growing attention owing to their immense potential applications in nanoscale electronic devices. Here, we report a novel route to mechanically manipulate polar structures via flexoelectricity in wrinkled thin films. Our results present a flexoelectric polar transition from a nonpolar state to uniaxial polar stripes, biaxial meronlike or antimeronlike polar structures, and polar labyrinths by varying wrinkle morphologies. The evolution mechanisms and the outstanding mechanical tunability of these flexoelectric polar patterns were investigated theoretically and numerically. This strategy based on flexoelectricity for generating nontrivial polar structures will no longer rely on the superlattice structure and can be widely applicable to all centrosymmetric or noncentrosymmetric materials, providing a broader range of material and structure candidates for polar topologies.
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Affiliation(s)
- Hongxing Shang
- State Key Laboratory for Strength and Vibration of Mechanical Structures, School of Aerospace Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Huiting Dong
- State Key Laboratory for Strength and Vibration of Mechanical Structures, School of Aerospace Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Yihan Wu
- State Key Laboratory for Strength and Vibration of Mechanical Structures, School of Aerospace Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Feng Deng
- State Key Laboratory for Strength and Vibration of Mechanical Structures, School of Aerospace Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Xu Liang
- State Key Laboratory for Strength and Vibration of Mechanical Structures, School of Aerospace Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Shuling Hu
- State Key Laboratory for Strength and Vibration of Mechanical Structures, School of Aerospace Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Shengping Shen
- State Key Laboratory for Strength and Vibration of Mechanical Structures, School of Aerospace Engineering, Xi'an Jiaotong University, Xi'an 710049, China
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11
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Xu T, Wu C, Zheng S, Wang Y, Wang J, Hirakata H, Kitamura T, Shimada T. Mechanical Rippling for Diverse Ferroelectric Topologies in Otherwise Nonferroelectric SrTiO_{3} Nanofilms. PHYSICAL REVIEW LETTERS 2024; 132:086801. [PMID: 38457703 DOI: 10.1103/physrevlett.132.086801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 12/18/2023] [Accepted: 01/12/2024] [Indexed: 03/10/2024]
Abstract
Polar topological structures such as skyrmions and merons have become an emerging research field due to their rich functionalities and promising applications in information storage. Up to now, the obtained polar topological structures are restricted to a few limited ferroelectrics with complex heterostructures, limiting their large-scale practical applications. Here, we circumvent this limitation by utilizing a nanoscale ripple-generated flexoelectric field as a universal means to create rich polar topological configurations in nonpolar nanofilms in a controllable fashion. Our extensive phase-field simulations show that a rippled SrTiO_{3} nanofilm with a single bulge activates polarizations that are stabilized in meron configurations, which further undergo topological transitions to Néel-type and Bloch-type skyrmions upon varying the geometries. The formation of these topologies originates from the curvature-dependent flexoelectric field, which extends beyond the common mechanism of geometric confinement that requires harsh energy conditions and strict temperature ranges. We further demonstrate that the rippled nanofilm with three-dimensional ripple patterns can accommodate other unreported modulated phases of ferroelectric topologies, which provide ferroelectric analogs to the complex spin topologies in magnets. The present study not only unveils the intriguing nanoscale electromechanical properties but also opens exciting opportunities to design various functional topological phenomena in flexible materials.
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Affiliation(s)
- Tao Xu
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
| | - Chengsheng Wu
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
- College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014, China
| | - Sizheng Zheng
- Department of Engineering Mechanics, School of Aeronautics and Astronautics, Zhejiang University, Hangzhou 310027, China
| | - Yu Wang
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
| | - Jie Wang
- Department of Engineering Mechanics, School of Aeronautics and Astronautics, Zhejiang University, Hangzhou 310027, China
- Zhejiang Laboratory, Hangzhou 311100, Zhejiang, China
| | - Hiroyuki Hirakata
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
| | - Takayuki Kitamura
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
| | - Takahiro Shimada
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
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12
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Wang S, Li W, Deng C, Hong Z, Gao HB, Li X, Gu Y, Zheng Q, Wu Y, Evans PG, Li JF, Nan CW, Li Q. Giant electric field-induced second harmonic generation in polar skyrmions. Nat Commun 2024; 15:1374. [PMID: 38355699 PMCID: PMC10866987 DOI: 10.1038/s41467-024-45755-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 02/04/2024] [Indexed: 02/16/2024] Open
Abstract
Electric field-induced second harmonic generation allows electrically controlling nonlinear light-matter interactions crucial for emerging integrated photonics applications. Despite its wide presence in materials, the figures-of-merit of electric field-induced second harmonic generation are yet to be elevated to enable novel device functionalities. Here, we show that the polar skyrmions, a topological phase spontaneously formed in PbTiO3/SrTiO3 ferroelectric superlattices, exhibit a high comprehensive electric field-induced second harmonic generation performance. The second-order nonlinear susceptibility and modulation depth, measured under non-resonant 800 nm excitation, reach ~54.2 pm V-1 and ~664% V-1, respectively, and high response bandwidth (higher than 10 MHz), wide operating temperature range (up to ~400 K) and good fatigue resistance (>1010 cycles) are also demonstrated. Through combined in-situ experiments and phase-field simulations, we establish the microscopic links between the exotic polarization configuration and field-induced transition paths of the skyrmions and their electric field-induced second harmonic generation response. Our study not only presents a highly competitive thin-film material ready for constructing on-chip devices, but opens up new avenues of utilizing topological polar structures in the fields of photonics and optoelectronics.
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Affiliation(s)
- Sixu Wang
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, 100084, Beijing, China
| | - Wei Li
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, 100084, Beijing, China
| | - Chenguang Deng
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, 100084, Beijing, China
| | - Zijian Hong
- School of Materials Science and Engineering, Zhejiang University, 310027, Hangzhou, China.
- Research Institute of Zhejiang University-Taizhou, 318000, Taizhou, Zhejiang, China.
| | - Han-Bin Gao
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, 100190, Beijing, China
| | - Xiaolong Li
- Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, 201204, Shanghai, China
| | - Yueliang Gu
- Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, 201204, Shanghai, China
| | - Qiang Zheng
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, 100190, Beijing, China.
| | - Yongjun Wu
- School of Materials Science and Engineering, Zhejiang University, 310027, Hangzhou, China
| | - Paul G Evans
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Jing-Feng Li
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, 100084, Beijing, China
| | - Ce-Wen Nan
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, 100084, Beijing, China
| | - Qian Li
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, 100084, Beijing, China.
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13
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Ren J, Tang S, Guo C, Wang J, Huang H. Surface Effect of Thickness-Dependent Polarization and Domain Evolution in BiFeO 3 Epitaxial Ultrathin Films. ACS APPLIED MATERIALS & INTERFACES 2024; 16:1074-1081. [PMID: 38149600 DOI: 10.1021/acsami.3c14561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2023]
Abstract
With the trend of device miniaturization, ultrathin ferroelectric films are gaining more and more attention. However, understanding ferroelectricity in this nanoscale context remains a formidable challenge, primarily due to the heightened relevance of surface effects, which often leads to the loss of net polarization. Here, the influence of surface effects on the polarization as a function of thickness in ultrathin BiFeO3 films is investigated using phase-field simulations. The findings reveal a notable increase in ferroelectric polarization with increasing thickness, with a particularly discernible change occurring below the 10 nm threshold. Upon accounting for surface effects, the polarization is marginally lower than the case without such considerations, with the disparity becoming more pronounced at smaller thicknesses. Moreover, the hysteresis loop and butterfly loop of the ultrathin film were simulated, demonstrating that the ferroelectric properties of films remain robust even down to a thickness of 5 nm. Our investigations provide valuable insights into the significance of ferroelectric thin films in device miniaturization.
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Affiliation(s)
- Jing Ren
- School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China
- Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, China
| | - Shiyu Tang
- School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China
- Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, China
| | - Changqing Guo
- School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China
- Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, China
| | - Jing Wang
- School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China
- Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, China
| | - Houbing Huang
- School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China
- Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, China
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14
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Guo M, Xu E, Huang H, Guo C, Chen H, Chen S, He S, Zhou L, Ma J, Shen Z, Xu B, Yi D, Gao P, Nan CW, Mathur ND, Shen Y. Electrically and mechanically driven rotation of polar spirals in a relaxor ferroelectric polymer. Nat Commun 2024; 15:348. [PMID: 38191601 PMCID: PMC10774403 DOI: 10.1038/s41467-023-44395-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 12/12/2023] [Indexed: 01/10/2024] Open
Abstract
Topology created by quasi-continuous spatial variations of a local polarization direction represents an exotic state of matter, but field-driven manipulation has been hitherto limited to creation and destruction. Here we report that relatively small electric or mechanical fields can drive the non-volatile rotation of polar spirals in discretized microregions of the relaxor ferroelectric polymer poly(vinylidene fluoride-ran-trifluoroethylene). These polar spirals arise from the asymmetric Coulomb interaction between vertically aligned helical polymer chains, and can be rotated in-plane through various angles with robust retention. Given also that our manipulation of topological order can be detected via infrared absorption, our work suggests a new direction for the application of complex materials.
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Affiliation(s)
- Mengfan Guo
- State Key Lab of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, 100084, Beijing, China.
- Department of Materials Science, University of Cambridge, 27 Charles Babbage Road, CB3 0FS, Cambridge, UK.
| | - Erxiang Xu
- State Key Lab of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, 100084, Beijing, China
| | - Houbing Huang
- School of Materials Science and Engineering & Advanced Research Institute of Multidisciplinary Science; Beijing Institute of Technology, 100081, Beijing, China
| | - Changqing Guo
- School of Materials Science and Engineering & Advanced Research Institute of Multidisciplinary Science; Beijing Institute of Technology, 100081, Beijing, China
| | - Hetian Chen
- State Key Lab of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, 100084, Beijing, China
| | - Shulin Chen
- Changsha Semiconductor Technology and Application Innovation Research Institute, College of Semiconductors (College of Integrated Circuits), Hunan University, 410082, Changsha, China
| | - Shan He
- State Key Lab of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, 100084, Beijing, China
| | - Le Zhou
- State Key Lab of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, 100084, Beijing, China
| | - Jing Ma
- State Key Lab of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, 100084, Beijing, China
| | - Zhonghui Shen
- International School of Materials Science and Engineering, Wuhan University of Technology, 430070, Wuhan, China
| | - Ben Xu
- Department of Graduate School, China Academy of Engineering Physics, 100193, Beijing, China
| | - Di Yi
- State Key Lab of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, 100084, Beijing, China
| | - Peng Gao
- Electron Microscopy Laboratory and International Center for Quantum Materials, School of Physics, Peking University, 100871, Beijing, China
| | - Ce-Wen Nan
- State Key Lab of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, 100084, Beijing, China
| | - Neil D Mathur
- Department of Materials Science, University of Cambridge, 27 Charles Babbage Road, CB3 0FS, Cambridge, UK.
| | - Yang Shen
- State Key Lab of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, 100084, Beijing, China.
- Center for Flexible Electronics Technology, Tsinghua University, 100084, Beijing, China.
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15
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Gao Z, Zhang Y, Li X, Zhang X, Chen X, Du G, Hou F, Gu B, Lun Y, Zhao Y, Zhao Y, Qu Z, Jin K, Wang X, Chen Y, Liu Z, Huang H, Gao P, Mostovoy M, Hong J, Cheong SW, Wang X. Mechanical manipulation for ordered topological defects. SCIENCE ADVANCES 2024; 10:eadi5894. [PMID: 38170776 PMCID: PMC10796077 DOI: 10.1126/sciadv.adi5894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 12/01/2023] [Indexed: 01/05/2024]
Abstract
Randomly distributed topological defects created during the spontaneous symmetry breaking are the fingerprints to trace the evolution of symmetry, range of interaction, and order parameters in condensed matter systems. However, the effective mean to manipulate topological defects into ordered form is elusive due to the topological protection. Here, we establish a strategy to effectively align the topological domain networks in hexagonal manganites through a mechanical approach. It is found that the nanoindentation strain gives rise to a threefold Magnus-type force distribution, leading to a sixfold symmetric domain pattern by driving the vortex and antivortex in opposite directions. On the basis of this rationale, sizeable mono-chirality topological stripe is readily achieved by expanding the nanoindentation to scratch, directly transferring the randomly distributed topological defects into an ordered form. This discovery provides a mechanical strategy to manipulate topological protected domains not only on ferroelectrics but also on ferromagnets/antiferromagnets and ferroelastics.
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Affiliation(s)
- Ziyan Gao
- School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Yixuan Zhang
- School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Xiaomei Li
- Electron Microscopy Laboratory and International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Xiangping Zhang
- School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Xue Chen
- Engineering Research Center for Semiconductor Integrated Technology, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Guoshuai Du
- Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, China
| | - Fei Hou
- Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, China
| | - Baijun Gu
- School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Yingzhuo Lun
- School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Yao Zhao
- School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Yingtao Zhao
- School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Zhaoliang Qu
- Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing 100081, China
| | - Ke Jin
- Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, China
| | - Xiaolei Wang
- Department of Physics and Optoelectronics, Faculty of Science, Beijing University of Technology, Beijing 100124, China
| | - Yabin Chen
- Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, China
| | - Zhanwei Liu
- School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Houbing Huang
- Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, China
| | - Peng Gao
- Electron Microscopy Laboratory and International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Maxim Mostovoy
- Zernile Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, Netherlands
| | - Jiawang Hong
- School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Sang-Wook Cheong
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, NJ 08854, USA
| | - Xueyun Wang
- School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081, China
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16
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Wang Z, Chen LQ. Reversible Phase Transition between Vortex Lattice and Hexagonal Polar Skyrmion Crystals. NANO LETTERS 2023; 23:9907-9911. [PMID: 37883233 DOI: 10.1021/acs.nanolett.3c02852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2023]
Abstract
Polar skyrmions in oxide heterostructures have recently attracted extensive interest due to their unique physical properties and potential applications. Here, we report the formation of the vortex lattice and the nanoscale polar skyrmion crystals with two-dimensional hexagonal symmetry in PbTiO3/SrTrO3 (PTO/STO) superlattices. Under an increasing external field, the system transitions from a vortex lattice phase to hexagonal polar skyrmion crystals (PSkC). The formation and annihilation process of the polar skyrmion crystals resemble the structural phase transition observed in atomic crystals. A temperature-electric field topological phase diagram is constructed, demonstrating stabilization of the vortex lattice and polar skyrmion crystals in a wide temperature and electric-field range. This study demonstrates the potential of manipulating the topological phase transition and its long-range order through an external field.
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Affiliation(s)
- Zhiyang Wang
- Department of Materials Science and Engineering, Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Long-Qing Chen
- Department of Materials Science and Engineering, Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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17
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Linker TM, Nomura KI, Fukushima S, Kalia RK, Krishnamoorthy A, Nakano A, Shimamura K, Shimojo F, Vashishta P. Induction and Ferroelectric Switching of Flux Closure Domains in Strained PbTiO 3 with Neural Network Quantum Molecular Dynamics. NANO LETTERS 2023; 23:7456-7462. [PMID: 37556684 DOI: 10.1021/acs.nanolett.3c01885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/11/2023]
Abstract
We have developed an extension of the Neural Network Quantum Molecular Dynamics (NNQMD) simulation method to incorporate electric-field dynamics based on Born effective charge (BEC), called NNQMD-BEC. We first validate NNQMD-BEC for the switching mechanisms of archetypal ferroelectric PbTiO3 bulk crystal and 180° domain walls (DWs). NNQMD-BEC simulations correctly describe the nucleation-and-growth mechanism during DW switching. In triaxially strained PbTiO3 with strain conditions commonly seen in many superlattice configurations, we find that flux-closure texture can be induced with application of an electric field perpendicular to the original polarization direction. Upon field reversal, the flux-closure texture switches via a pair of transient vortices as the intermediate state, indicating an energy-efficient switching pathway. Our NNQMD-BEC method provides a theoretical guidance to study electro-mechano effects with existing machine learning force fields using a simple BEC extension, which will be relevant for engineering applications such as field-controlled switching in mechanically strained ferroelectric devices.
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Affiliation(s)
- Thomas M Linker
- Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, California 90089-0242, United States
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Ken-Ichi Nomura
- Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, California 90089-0242, United States
| | - Shogo Fukushima
- Department of Physics, Kumamoto University, Kumamoto 860-8555, Japan
| | - Rajiv K Kalia
- Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, California 90089-0242, United States
| | - Aravind Krishnamoorthy
- Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, California 90089-0242, United States
| | - Aiichiro Nakano
- Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, California 90089-0242, United States
| | - Kohei Shimamura
- Department of Physics, Kumamoto University, Kumamoto 860-8555, Japan
| | - Fuyuki Shimojo
- Department of Physics, Kumamoto University, Kumamoto 860-8555, Japan
| | - Priya Vashishta
- Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, California 90089-0242, United States
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18
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Susarla S, Hsu S, Gómez-Ortiz F, García-Fernández P, Savitzky BH, Das S, Behera P, Junquera J, Ercius P, Ramesh R, Ophus C. The emergence of three-dimensional chiral domain walls in polar vortices. Nat Commun 2023; 14:4465. [PMID: 37491370 PMCID: PMC10368707 DOI: 10.1038/s41467-023-40009-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Accepted: 07/07/2023] [Indexed: 07/27/2023] Open
Abstract
Chirality or handedness of a material can be used as an order parameter to uncover the emergent electronic properties for quantum information science. Conventionally, chirality is found in naturally occurring biomolecules and magnetic materials. Chirality can be engineered in a topological polar vortex ferroelectric/dielectric system via atomic-scale symmetry-breaking operations. We use four-dimensional scanning transmission electron microscopy (4D-STEM) to map out the topology-driven three-dimensional domain walls, where the handedness of two neighbor topological domains change or remain the same. The nature of the domain walls is governed by the interplay of the local perpendicular (lateral) and parallel (axial) polarization with respect to the tubular vortex structures. Unique symmetry-breaking operations and the finite nature of domain walls result in a triple point formation at the junction of chiral and achiral domain walls. The unconventional nature of the domain walls with triple point pairs may result in unique electrostatic and magnetic properties potentially useful for quantum sensing applications.
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Affiliation(s)
- Sandhya Susarla
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, 94720, CA, USA.
- Materials Sciences Division, Lawrence Berkeley Laboratory, Berkeley, 94720, CA, USA.
- School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, 85280, AZ, USA.
| | - Shanglin Hsu
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, 94720, CA, USA
- Materials Sciences Division, Lawrence Berkeley Laboratory, Berkeley, 94720, CA, USA
| | - Fernando Gómez-Ortiz
- Departmento de Ciencias de la Tierra y Física de la Materia Condensada, Universidad de Cantabria, Cantabria Campus Internacional Santander, Santander, 39005, Spain
| | - Pablo García-Fernández
- Departmento de Ciencias de la Tierra y Física de la Materia Condensada, Universidad de Cantabria, Cantabria Campus Internacional Santander, Santander, 39005, Spain
| | - Benjamin H Savitzky
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, 94720, CA, USA
| | - Sujit Das
- Materials Research Centre, Indian Institute of Science, Bangalore, 560012, Karnataka, India
| | - Piush Behera
- Department of Materials Science & Engineering, University of California, Berkeley, 94720, CA, USA
| | - Javier Junquera
- Departmento de Ciencias de la Tierra y Física de la Materia Condensada, Universidad de Cantabria, Cantabria Campus Internacional Santander, Santander, 39005, Spain
| | - Peter Ercius
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, 94720, CA, USA
| | - Ramamoorthy Ramesh
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, 94720, CA, USA.
- Materials Sciences Division, Lawrence Berkeley Laboratory, Berkeley, 94720, CA, USA.
- Department of Physics, University of California, Berkeley, Berkeley, 94720, CA, USA.
- Department of Physics, Rice University, Houston, 77005, TX, USA.
- Department of Materials Science and Nanoengineering, Houston, 77005, TX, USA.
| | - Colin Ophus
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, 94720, CA, USA.
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19
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Govinden V, Tong P, Guo X, Zhang Q, Mantri S, Seyfouri MM, Prokhorenko S, Nahas Y, Wu Y, Bellaiche L, Sun T, Tian H, Hong Z, Valanoor N, Sando D. Ferroelectric solitons crafted in epitaxial bismuth ferrite superlattices. Nat Commun 2023; 14:4178. [PMID: 37443322 DOI: 10.1038/s41467-023-39841-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 06/29/2023] [Indexed: 07/15/2023] Open
Abstract
In ferroelectrics, complex interactions among various degrees of freedom enable the condensation of topologically protected polarization textures. Known as ferroelectric solitons, these particle-like structures represent a new class of materials with promise for beyond-CMOS technologies due to their ultrafine size and sensitivity to external stimuli. Such polarization textures have scarcely been demonstrated in multiferroics. Here, we present evidence for ferroelectric solitons in (BiFeO3)/(SrTiO3) superlattices. High-resolution piezoresponse force microscopy and Cs-corrected high-angle annular dark-field scanning transmission electron microscopy reveal a zoo of topologies, and polarization displacement mapping of planar specimens reveals center-convergent/divergent topological defects as small as 3 nm. Phase-field simulations verify that some of these structures can be classed as bimerons with a topological charge of ±1, and first-principles-based effective Hamiltonian computations show that the coexistence of such structures can lead to non-integer topological charges, a first observation in a BiFeO3-based system. Our results open new opportunities in multiferroic topotronics.
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Affiliation(s)
- Vivasha Govinden
- School of Materials Science and Engineering, University of New South Wales Sydney, Kensington, NSW, Australia
| | - Peiran Tong
- Center of Electron Microscopy, School of Materials Science and Engineering, State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xiangwei Guo
- School of Materials Science and Engineering, Zhejiang University, Hangzhou, Zhejiang, China
- Institute of Advanced Semiconductors & Zhejiang Provincial Key Laboratory of Power Semiconductor Materials and Devices, Hangzhou Innovation Center, Zhejiang University, Hangzhou, Zhejiang, China
- Cyrus Tang Center for Sensor Materials and Applications, State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou, Zhejiang, China
| | - Qi Zhang
- School of Materials Science and Engineering, University of New South Wales Sydney, Kensington, NSW, Australia
| | - Sukriti Mantri
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, AR, USA
| | - Mohammad Moein Seyfouri
- School of Materials Science and Engineering, University of New South Wales Sydney, Kensington, NSW, Australia
- Solid State and Elemental Analysis Unit, Mark Wainwright Analytical Center, University of New South Wales, Sydney, NSW, Australia
| | - Sergei Prokhorenko
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, AR, USA
| | - Yousra Nahas
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, AR, USA
| | - Yongjun Wu
- School of Materials Science and Engineering, Zhejiang University, Hangzhou, Zhejiang, China
- Cyrus Tang Center for Sensor Materials and Applications, State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou, Zhejiang, China
| | - Laurent Bellaiche
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, AR, USA
| | - Tulai Sun
- Center of Electron Microscopy, School of Materials Science and Engineering, State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou, Zhejiang, China
- Center for Electron Microscopy, State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology and College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang, China
| | - He Tian
- Center of Electron Microscopy, School of Materials Science and Engineering, State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou, Zhejiang, China.
- School of Physics and Microelectronics, Zhengzhou University, Zhengzhou, Henan, China.
| | - Zijian Hong
- School of Materials Science and Engineering, Zhejiang University, Hangzhou, Zhejiang, China.
- Cyrus Tang Center for Sensor Materials and Applications, State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou, Zhejiang, China.
| | - Nagarajan Valanoor
- School of Materials Science and Engineering, University of New South Wales Sydney, Kensington, NSW, Australia.
| | - Daniel Sando
- School of Materials Science and Engineering, University of New South Wales Sydney, Kensington, NSW, Australia.
- School of Physical and Chemical Sciences, University of Canterbury, Christchurch, New Zealand.
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20
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Wang J, Liang D, Ma J, Fan Y, Ma J, Jafri HM, Yang H, Zhang Q, Wang Y, Guo C, Dong S, Liu D, Wang X, Hong J, Zhang N, Gu L, Yi D, Zhang J, Lin Y, Chen LQ, Huang H, Nan CW. Polar Solomon rings in ferroelectric nanocrystals. Nat Commun 2023; 14:3941. [PMID: 37402744 DOI: 10.1038/s41467-023-39668-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Accepted: 06/22/2023] [Indexed: 07/06/2023] Open
Abstract
Solomon rings, upholding the symbol of wisdom with profound historical roots, were widely used as decorations in ancient architecture and clothing. However, it was only recently discovered that such topological structures can be formed by self-organization in biological/chemical molecules, liquid crystals, etc. Here, we report the observation of polar Solomon rings in a ferroelectric nanocrystal, which consist of two intertwined vortices and are mathematically equivalent to a [Formula: see text] link in topology. By combining piezoresponse force microscopy observations and phase-field simulations, we demonstrate the reversible switching between polar Solomon rings and vertex textures by an electric field. The two types of topological polar textures exhibit distinct absorption of terahertz infrared waves, which can be exploited in infrared displays with a nanoscale resolution. Our study establishes, both experimentally and computationally, the existence and electrical manipulation of polar Solomon rings, a new form of topological polar structures that may provide a simple way for fast, robust, and high-resolution optoelectronic devices.
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Affiliation(s)
- Jing Wang
- Advanced Research Institute of Multidisciplinary Science, and School of Materials Science and Engineering, Beijing Institute of Technology, 100081, Beijing, China
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, 100084, Beijing, China
| | - Deshan Liang
- Advanced Research Institute of Multidisciplinary Science, and School of Materials Science and Engineering, Beijing Institute of Technology, 100081, Beijing, China
| | - Jing Ma
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, 100084, Beijing, China
| | - Yuanyuan Fan
- Advanced Research Institute of Multidisciplinary Science, and School of Materials Science and Engineering, Beijing Institute of Technology, 100081, Beijing, China
| | - Ji Ma
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, 100084, Beijing, China
- School of Material Science and Engineering, Kunming University of Science and Technology, 650093, Kunming, Yunnan, China
| | - Hasnain Mehdi Jafri
- Advanced Research Institute of Multidisciplinary Science, and School of Materials Science and Engineering, Beijing Institute of Technology, 100081, Beijing, China
| | - Huayu Yang
- Advanced Research Institute of Multidisciplinary Science, and School of Materials Science and Engineering, Beijing Institute of Technology, 100081, Beijing, China
| | - Qinghua Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Science, 100190, Beijing, China
| | - Yue Wang
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, 100084, Beijing, China
| | - Changqing Guo
- Advanced Research Institute of Multidisciplinary Science, and School of Materials Science and Engineering, Beijing Institute of Technology, 100081, Beijing, China
| | - Shouzhe Dong
- Advanced Research Institute of Multidisciplinary Science, and School of Materials Science and Engineering, Beijing Institute of Technology, 100081, Beijing, China
| | - Di Liu
- Advanced Research Institute of Multidisciplinary Science, and School of Materials Science and Engineering, Beijing Institute of Technology, 100081, Beijing, China
| | - Xueyun Wang
- School of Aerospace Engineering, Beijing Institute of Technology, 100081, Beijing, China
| | - Jiawang Hong
- School of Aerospace Engineering, Beijing Institute of Technology, 100081, Beijing, China
| | - Nan Zhang
- Beijing Engineering Research Center of Mixed Reality and Advanced Display, and School of Optics and Photonics, Beijing Institute of Technology, 100081, Beijing, China
| | - Lin Gu
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, 100084, Beijing, China
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Science, 100190, Beijing, China
| | - Di Yi
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, 100084, Beijing, China
| | - Jinxing Zhang
- Department of Physics, and Key Laboratory of Multi-scale Spin Physics, Ministry of Education, Beijing Normal University, 100875, Beijing, China
| | - Yuanhua Lin
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, 100084, Beijing, China
| | - Long-Qing Chen
- Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA, 16802, USA
| | - Houbing Huang
- Advanced Research Institute of Multidisciplinary Science, and School of Materials Science and Engineering, Beijing Institute of Technology, 100081, Beijing, China.
| | - Ce-Wen Nan
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, 100084, Beijing, China.
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21
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Gong FH, Tang YL, Wang YJ, Chen YT, Wu B, Yang LX, Zhu YL, Ma XL. Absence of critical thickness for polar skyrmions with breaking the Kittel's law. Nat Commun 2023; 14:3376. [PMID: 37291226 PMCID: PMC10250330 DOI: 10.1038/s41467-023-39169-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 05/31/2023] [Indexed: 06/10/2023] Open
Abstract
The period of polar domain (d) in ferroics was commonly believed to scale with corresponding film thicknesses (h), following the classical Kittel's law of d ∝ [Formula: see text]. Here, we have not only observed that this relationship fails in the case of polar skyrmions, where the period shrinks nearly to a constant value, or even experiences a slight increase, but also discovered that skyrmions have further persisted in [(PbTiO3)2/(SrTiO3)2]10 ultrathin superlattices. Both experimental and theoretical results indicate that the skyrmion periods (d) and PbTiO3 layer thicknesses in superlattice (h) obey the hyperbolic function of d = Ah + [Formula: see text] other than previous believed, simple square root law. Phase-field analysis indicates that the relationship originates from the different energy competitions of the superlattices with PbTiO3 layer thicknesses. This work exemplified the critical size problems faced by nanoscale ferroelectric device designing in the post-Moore era.
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Affiliation(s)
- Feng-Hui Gong
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang, 110016, China
- School of Materials Science and Engineering, University of Science and Technology of China, Wenhua Road 72, Shenyang, 110016, China
| | - Yun-Long Tang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang, 110016, China
| | - Yu-Jia Wang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang, 110016, China
| | - Yu-Ting Chen
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang, 110016, China
- School of Materials Science and Engineering, University of Science and Technology of China, Wenhua Road 72, Shenyang, 110016, China
| | - Bo Wu
- Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan, 523808, Guangdong, China
| | - Li-Xin Yang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang, 110016, China
| | - Yin-Lian Zhu
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang, 110016, China.
- Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan, 523808, Guangdong, China.
| | - Xiu-Liang Ma
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang, 110016, China.
- Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan, 523808, Guangdong, China.
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
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22
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Yuan S, Chen Z, Prokhorenko S, Nahas Y, Bellaiche L, Liu C, Xu B, Chen L, Das S, Martin LW. Hexagonal Close-Packed Polar-Skyrmion Lattice in Ultrathin Ferroelectric PbTiO_{3} Films. PHYSICAL REVIEW LETTERS 2023; 130:226801. [PMID: 37327425 DOI: 10.1103/physrevlett.130.226801] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 02/24/2023] [Accepted: 05/05/2023] [Indexed: 06/18/2023]
Abstract
Polar skyrmions are topologically stable, swirling polarization textures with particlelike characteristics, which hold promise for next-generation, nanoscale logic and memory. However, the understanding of how to create ordered polar skyrmion lattice structures and how such structures respond to applied electric fields, temperature, and film thickness remains elusive. Here, using phase-field simulations, the evolution of polar topology and the emergence of a phase transition to a hexagonal close-packed skyrmion lattice is explored through the construction of a temperature-electric field phase diagram for ultrathin ferroelectric PbTiO_{3} films. The hexagonal-lattice skyrmion crystal can be stabilized under application of an external, out-of-plane electric field which carefully adjusts the delicate interplay of elastic, electrostatic, and gradient energies. In addition, the lattice constants of the polar skyrmion crystals are found to increase with film thickness, consistent with expectation from Kittel's law. Our studies pave the way for the development of novel ordered condensed matter phases assembled from topological polar textures and related emergent properties in nanoscale ferroelectrics.
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Affiliation(s)
- Shuai Yuan
- School of Materials Science and Engineering, Harbin Institute of Technology, Shenzhen 518055, China and Flexible Printed Electronics Technology Center, Harbin Institute of Technology, Shenzhen 518055, China
| | - Zuhuang Chen
- School of Materials Science and Engineering, Harbin Institute of Technology, Shenzhen 518055, China and Flexible Printed Electronics Technology Center, Harbin Institute of Technology, Shenzhen 518055, China
| | - Sergei Prokhorenko
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - Yousra Nahas
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - Laurent Bellaiche
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - Chenhan Liu
- Micro- and Nano-scale Thermal Measurement and Thermal Management Laboratory, School of Energy and Mechanical Engineering, Nanjing Normal University, Nanjing, 210046, People's Republic of China
| | - Bin Xu
- Institute of Theoretical and Applied Physics and School of Physical Science and Technology, Soochow University, Suzhou, Jiangsu 215006, China
| | - Lang Chen
- Department of Physics, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Sujit Das
- Materials Research Centre, Indian Institute of Science, Bangalore, 560012, India
| | - Lane W Martin
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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23
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Behera P, Parsonnet E, Gómez-Ortiz F, Srikrishna V, Meisenheimer P, Susarla S, Kavle P, Caretta L, Wu Y, Tian Z, Fernandez A, Martin LW, Das S, Junquera J, Hong Z, Ramesh R. Emergent Ferroelectric Switching Behavior from Polar Vortex Lattice. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2208367. [PMID: 36930962 DOI: 10.1002/adma.202208367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 03/08/2023] [Indexed: 06/09/2023]
Abstract
Topologically protected polar textures have provided a rich playground for the exploration of novel, emergent phenomena. Recent discoveries indicate that ferroelectric vortices and skyrmions not only host properties markedly different from traditional ferroelectrics, but also that these properties can be harnessed for unique memory devices. Using a combination of capacitor-based capacitance measurements and computational models, it is demonstrated that polar vortices in dielectric-ferroelectric-dielectric trilayers exhibit classical ferroelectric bi-stability together with the existence of low-field metastable polarization states. This behavior is directly tied to the in-plane vortex ordering, and it is shown that it can be used as a new method of non-destructive readout-out of the poled state.
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Affiliation(s)
- Piush Behera
- Department of Materials Science and Engineering, University of California Berkeley, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Eric Parsonnet
- Department of Physics, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Fernando Gómez-Ortiz
- Department of Earth Sciences and Condensed Matter Physics, Universidad de Cantabria, Cantabria Campus Internacional, 39005, Santander, Spain
| | - Vishantak Srikrishna
- Department of Physics, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Peter Meisenheimer
- Department of Materials Science and Engineering, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Sandhya Susarla
- Department of Materials Science and Engineering, University of California Berkeley, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Pravin Kavle
- Department of Materials Science and Engineering, University of California Berkeley, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Lucas Caretta
- Department of Materials Science and Engineering, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Yongjun Wu
- Cyrus Tang Center for Sensor Materials and Applications, State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, 310027, Hangzhou, China
| | - Zishen Tian
- Department of Materials Science and Engineering, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Abel Fernandez
- Department of Materials Science and Engineering, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Lane W Martin
- Department of Materials Science and Engineering, University of California Berkeley, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Sujit Das
- Materials Research Centre, Indian Institute of Science, Bangalore, Karnataka, 560012, India
| | - Javier Junquera
- Department of Earth Sciences and Condensed Matter Physics, Universidad de Cantabria, Cantabria Campus Internacional, 39005, Santander, Spain
| | - Zijian Hong
- Cyrus Tang Center for Sensor Materials and Applications, State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, 310027, Hangzhou, China
| | - Ramamoorthy Ramesh
- Department of Materials Science and Engineering, University of California Berkeley, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Physics, University of California Berkeley, Berkeley, CA, 94720, USA
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24
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Bennett D, Chaudhary G, Slager RJ, Bousquet E, Ghosez P. Polar meron-antimeron networks in strained and twisted bilayers. Nat Commun 2023; 14:1629. [PMID: 36959197 PMCID: PMC10036565 DOI: 10.1038/s41467-023-37337-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 03/13/2023] [Indexed: 03/25/2023] Open
Abstract
Out-of-plane polar domain structures have recently been discovered in strained and twisted bilayers of inversion symmetry broken systems such as hexagonal boron nitride. Here we show that this symmetry breaking also gives rise to an in-plane component of polarization, and the form of the total polarization is determined purely from symmetry considerations. The in-plane component of the polarization makes the polar domains in strained and twisted bilayers topologically non-trivial, forming a network of merons and antimerons (half-skyrmions and half-antiskyrmions). For twisted systems, the merons are of Bloch type whereas for strained systems they are of Néel type. We propose that the polar domains in strained or twisted bilayers may serve as a platform for exploring topological physics in layered materials and discuss how control over topological phases and phase transitions may be achieved in such systems.
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Affiliation(s)
- Daniel Bennett
- Physique Théorique des Matériaux, QMAT, CESAM, University of Liège, B-4000, Sart-Tilman, Belgium.
- Theory of Condensed Matter Group, Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0HE, UK.
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA.
| | - Gaurav Chaudhary
- Theory of Condensed Matter Group, Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0HE, UK
| | - Robert-Jan Slager
- Theory of Condensed Matter Group, Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0HE, UK
| | - Eric Bousquet
- Physique Théorique des Matériaux, QMAT, CESAM, University of Liège, B-4000, Sart-Tilman, Belgium
| | - Philippe Ghosez
- Physique Théorique des Matériaux, QMAT, CESAM, University of Liège, B-4000, Sart-Tilman, Belgium
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25
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Berškys J, Orlov S. Accelerating Airy beams with particle-like polarization topologies and free-space bimeronic lattices. OPTICS LETTERS 2023; 48:1168-1171. [PMID: 36857240 DOI: 10.1364/ol.483339] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 01/24/2023] [Indexed: 06/18/2023]
Abstract
Phase and polarization singularities in electromagnetic waves are usually attributed to one-dimensional topologies-lines, knots, and braids. Recently, particle-like structures have been predicted and observed: optical Skyrmions, vortices with spherical polarization, etc. In this article, we devise vector Airy beams with point-like singularity in the focal plane, thus leading to the presence of a particle-like topology. We present an extensive analytical analysis of the spatial spectra and focal structure of such beams. We report on the presence of a free-space lattice of bimerons in such vector Airy beams.
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26
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Li YQ, Wang P, Zhang H, Zhang H, Fu LB. Nonabelian Ginzburg-Landau theory for ferroelectrics. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 35:155702. [PMID: 36731170 DOI: 10.1088/1361-648x/acb89d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 02/01/2023] [Indexed: 06/18/2023]
Abstract
The Ginzburg-Landau theory, which was introduced to phenomenologically describe the destruction of superconductivity by a magnetic field at the beginning, has brought up much more knowledge beyond the original one as a mean-field theory of thermodynamics states. There the complex order parameter plays an important role. Here we propose a macroscopic theory to describe the features of ferroelectrics by a two-component complex order parameter coupled to nonabelian gauge potentials that provide more freedom to reflect interplays between different measurables. Within this theoretical framework, some recently discovered empirical static and time-independent phenomena, such as vortex, anti-vortex, spiral orders can be obtained as solutions for different gauge potentials. It is expected to bring in a new angle of view with more elucidation than the traditional one that takes the polarization as order parameter.
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Affiliation(s)
- You-Quan Li
- Chern Institute of Mathematics, Nankai University, Weijin Road 94, Tianjin 300071, People's Republic of China
- School of Physics, Zhejiang University, Hangzhou 310027, People's Republic of China
- Collaborative Innovation Center of Advanced Microstructure, Nanjing University, Nanjing 210008, People's Republic of China
| | - Pei Wang
- Department of Physics, Zhejiang Normal University, Jinhua 321004, People's Republic of China
| | - Hua Zhang
- Center for Advanced Material Diagnostic Technology, Shenzhen Technology University, Shenzhen 518118, People's Republic of China
| | - Hong Zhang
- School of Physics, Zhejiang University, Hangzhou 310027, People's Republic of China
| | - Li-Bin Fu
- Graduate School of China Academy of Engineering Physics, Beijing 100193, People's Republic of China
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27
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Wang X, Huang K, Wu X, Yuan L, Li L, Li G, Feng S. Manipulation and observation of atomic-scale superlattices in perovskite manganate. CHINESE CHEM LETT 2023. [DOI: 10.1016/j.cclet.2023.108267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2023]
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28
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Liu J, Cao Y, Tang YL, Zhu YL, Wang Y, Liu N, Zou MJ, Shi TT, Liu F, Gong F, Feng YP, Ma XL. Room-Temperature Ferroelectricity of Paraelectric Oxides Tailored by Nano-Engineering. ACS APPLIED MATERIALS & INTERFACES 2023; 15:4226-4233. [PMID: 36633961 DOI: 10.1021/acsami.2c19944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Inducing clear ferroelectricity in the quantum paraelectric SrTiO3 is important for triggering methods to discover hidden phases in condensed matter physics. Several methods such as isotope substitution and freestanding membranes could introduce ferroelectricity in SrTiO3 toward nonvolatile memory applications. However, the stable transformation from quantum paraelectric SrTiO3 to ferroelectricity SrTiO3 at room temperature still remains challenging. Here, we used multiple nano-engineering in (SrTiO3)0.65/(CeO2)0.35 films to achieve an emergent room-temperature ferroelectricity. It is shown that the CeO2 nanocolumns impose large out-of-plane strains and induce Sr/O deficiency in the SrTiO3 matrix to form a clear tetragonal structure, which leads to an apparent room-temperature ferroelectric polarization up to 2.5 μC/cm2. In collaboration with density functional theory calculations, it is proposed that the compressive strains combined with elemental deficiency give rise to local redistribution of charge density and orbital order, which induce emergent tetragonality of the strained SrTiO3. Our work thus paves a pathway for architecting functional systems in perovskite oxides using a multiple nano-design.
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Affiliation(s)
- Jiaqi Liu
- Shenyang National Laboratory for Materials Science and Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
- School of Materials Science and Engineering, University of Science and Technology of China, Wenhua Road 72, Shenyang 110016, China
| | - Yi Cao
- Shenyang National Laboratory for Materials Science and Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
- School of Materials Science and Engineering, University of Science and Technology of China, Wenhua Road 72, Shenyang 110016, China
| | - Yun-Long Tang
- Shenyang National Laboratory for Materials Science and Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
| | - Yin-Lian Zhu
- Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan 523808, China
| | - Yujia Wang
- Shenyang National Laboratory for Materials Science and Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
| | - Nan Liu
- Shenyang National Laboratory for Materials Science and Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
- School of Materials Science and Engineering, University of Science and Technology of China, Wenhua Road 72, Shenyang 110016, China
| | - Min-Jie Zou
- Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan 523808, China
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Tong-Tong Shi
- Shenyang National Laboratory for Materials Science and Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
- School of Materials Science and Engineering, University of Science and Technology of China, Wenhua Road 72, Shenyang 110016, China
| | - Fang Liu
- Shenyang National Laboratory for Materials Science and Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
- School of Materials Science and Engineering, University of Science and Technology of China, Wenhua Road 72, Shenyang 110016, China
| | - Fenghui Gong
- Shenyang National Laboratory for Materials Science and Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
- School of Materials Science and Engineering, University of Science and Technology of China, Wenhua Road 72, Shenyang 110016, China
| | - Yan-Peng Feng
- Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan 523808, China
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Xiu-Liang Ma
- Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan 523808, China
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
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29
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Linker T, Nomura KI, Fukushima S, Kalia RK, Krishnamoorthy A, Nakano A, Shimamura K, Shimojo F, Vashishta P. Squishing Skyrmions: Symmetry-Guided Dynamic Transformation of Polar Topologies Under Compression. J Phys Chem Lett 2022; 13:11335-11345. [PMID: 36454058 DOI: 10.1021/acs.jpclett.2c03029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Mechanical controllability of recently discovered topological defects (e.g., skyrmions) in ferroelectric materials is of interest for the development of ultralow-power mechano-electronics that are protected against thermal noise. However, fundamental understanding is hindered by the "multiscale quantum challenge" to describe topological switching encompassing large spatiotemporal scales with quantum mechanical accuracy. Here, we overcome this challenge by developing a machine-learning-based multiscale simulation framework─a hybrid neural network quantum molecular dynamics (NNQMD) and molecular mechanics (MM) method. For nanostructures composed of SrTiO3 and PbTiO3, we find how the symmetry of mechanical loading essentially controls polar topological switching. We find under symmetry-breaking uniaxial compression a squishing-to-annihilation pathway versus formation of a topological composite named skyrmionium under symmetry-preserving isotropic compression. The distinct pathways are explained in terms of the underlying materials' elasticity and symmetry, as well as the Landau-Lifshitz-Kittel scaling law. Such rational control of ferroelectric topologies will likely facilitate exploration of the rich ferroelectric "topotronics" design space.
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Affiliation(s)
- Thomas Linker
- Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, California90089-0242, United States of America
| | - Ken-Ichi Nomura
- Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, California90089-0242, United States of America
| | - Shogo Fukushima
- Department of Physics, Kumamoto University, Kumamoto860-8555, Japan
| | - Rajiv K Kalia
- Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, California90089-0242, United States of America
| | - Aravind Krishnamoorthy
- Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, California90089-0242, United States of America
| | - Aiichiro Nakano
- Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, California90089-0242, United States of America
| | - Kohei Shimamura
- Department of Physics, Kumamoto University, Kumamoto860-8555, Japan
| | - Fuyuki Shimojo
- Department of Physics, Kumamoto University, Kumamoto860-8555, Japan
| | - Priya Vashishta
- Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, California90089-0242, United States of America
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30
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Geng WR, Guo X, Ge HL, Tang YL, Zhu Y, Wang Y, Wu B, Zou MJ, Feng YP, Ma XL. Real-Time Transformation of Flux-Closure Domains with Superhigh Thermal Stability. NANO LETTERS 2022; 22:8892-8899. [PMID: 36331549 DOI: 10.1021/acs.nanolett.2c02969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Polar topologies have received extensive attention due to their exotic configurations and functionalities. Understanding their responsive behaviors to external stimuli, especially thermal excitation, is highly desirable to extend their applications to high temperature, which is still unclear. Here, combining in situ transmission electron microscopy and phase-field simulations, the thermal dynamics of the flux-closure domains were illuminated in PbTiO3/SrTiO3 multilayers. In-depth analyses suggested that the topological transition processes from a/c domains to flux-closure quadrants were influenced by the boundary conditions of PbTiO3 layers. The symmetrical boundary condition stabilized the flux-closure domains at higher temperature than in the asymmetrical case. Furthermore, the reversible thermal responsive behaviors of the flux-closure domains displayed superior thermal stability, which maintained robust up to 450 °C (near the Curie temperature). This work provides new insights into the dynamics of polar topologies under thermal excitation and facilitates their applications as nanoelectronics under extreme conditions.
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Affiliation(s)
- Wan-Rong Geng
- Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan, Guangdong523808, People's Republic of China
- Institute of Physics, Chinese Academy of Sciences, Beijing100190, People's Republic of China
| | - Xiangwei Guo
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, 110016Shenyang, People's Republic of China
| | - Hua-Long Ge
- School of Materials and Energy, Yunnan University, Kunming, 650091, People's Republic of China
| | - Yun-Long Tang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, 110016Shenyang, People's Republic of China
| | - Yinlian Zhu
- Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan, Guangdong523808, People's Republic of China
| | - Yujia Wang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, 110016Shenyang, People's Republic of China
| | - Bo Wu
- Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan, Guangdong523808, People's Republic of China
| | - Min-Jie Zou
- Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan, Guangdong523808, People's Republic of China
- Institute of Physics, Chinese Academy of Sciences, Beijing100190, People's Republic of China
| | - Yan-Peng Feng
- Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan, Guangdong523808, People's Republic of China
- Institute of Physics, Chinese Academy of Sciences, Beijing100190, People's Republic of China
| | - Xiu-Liang Ma
- Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan, Guangdong523808, People's Republic of China
- Institute of Physics, Chinese Academy of Sciences, Beijing100190, People's Republic of China
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31
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Tikhonov Y, Maguire JR, McCluskey CJ, McConville JPV, Kumar A, Lu H, Meier D, Razumnaya A, Gregg JM, Gruverman A, Vinokur VM, Luk'yanchuk I. Polarization Topology at the Nominally Charged Domain Walls in Uniaxial Ferroelectrics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2203028. [PMID: 36114716 DOI: 10.1002/adma.202203028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Revised: 09/06/2022] [Indexed: 06/15/2023]
Abstract
Ferroelectric domain walls provide a fertile environment for novel materials physics. If a polarization discontinuity arises, it can drive a redistribution of electronic carriers and changes in band structure, which often result in emergent 2D conductivity. If such a discontinuity is not tolerated, then its amelioration usually involves the formation of complex topological patterns, such as flux-closure domains, dipolar vortices, skyrmions, merons, or Hopfions. The degrees of freedom required for the development of such patterns, in which dipolar rotation is a hallmark, are readily found in multiaxial ferroelectrics. In uniaxial ferroelectrics, where only two opposite polar orientations are possible, it has been assumed that discontinuities are unavoidable when antiparallel components of polarization meet. This perception has been borne out by the appearance of charged conducting domain walls in systems such as hexagonal manganites and lithium niobate. Here, experimental and theoretical investigations on lead germanate (Pb5 Ge3 O11 ) reveal that polar discontinuities can be obviated at head-to-head and tail-to-tail domain walls by mutual domain bifurcation along two different axes, creating a characteristic saddle-point domain wall morphology and associated novel dipolar topology, removing the need for screening charge accumulation and associated conductivity enhancement.
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Affiliation(s)
- Yurii Tikhonov
- University of Picardie, Laboratory of Condensed Matter Physics, Amiens, 80039, France
- Faculty of Physics, Southern Federal University, 5 Zorge Street, Rostov-on-Don, 344090, Russia
| | - Jesi R Maguire
- Centre for Nanostructured Media, School of Mathematics and Physics, Queen's University Belfast, Belfast, BT7 1NN, UK
| | - Conor J McCluskey
- Centre for Nanostructured Media, School of Mathematics and Physics, Queen's University Belfast, Belfast, BT7 1NN, UK
| | - James P V McConville
- Centre for Nanostructured Media, School of Mathematics and Physics, Queen's University Belfast, Belfast, BT7 1NN, UK
| | - Amit Kumar
- Centre for Nanostructured Media, School of Mathematics and Physics, Queen's University Belfast, Belfast, BT7 1NN, UK
| | - Haidong Lu
- Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Dennis Meier
- Department of Materials Science and Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, 7491, Norway
| | - Anna Razumnaya
- Jožef Stefan Institute, Jamova Cesta 39, Ljubljana, 1000, Slovenia
- Terra Quantum AG, Kornhausstrasse 25, St. Gallen, CH-9000, Switzerland
| | - John Martin Gregg
- Centre for Nanostructured Media, School of Mathematics and Physics, Queen's University Belfast, Belfast, BT7 1NN, UK
| | - Alexei Gruverman
- Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Valerii M Vinokur
- University of Picardie, Laboratory of Condensed Matter Physics, Amiens, 80039, France
- Terra Quantum AG, Kornhausstrasse 25, St. Gallen, CH-9000, Switzerland
- Physics Department, City College of the City University of New York, 160 Convent Avenue, New York, NY, 10031, USA
| | - Igor Luk'yanchuk
- University of Picardie, Laboratory of Condensed Matter Physics, Amiens, 80039, France
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32
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Electric-field control of the nucleation and motion of isolated three-fold polar vertices. Nat Commun 2022; 13:6340. [PMID: 36284138 PMCID: PMC9596422 DOI: 10.1038/s41467-022-33973-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 10/10/2022] [Indexed: 11/21/2022] Open
Abstract
Recently various topological polar structures have been discovered in oxide thin films. Despite the increasing evidence of their switchability under electrical and/or mechanical fields, the dynamic property of isolated ones, which is usually required for applications such as data storage, is still absent. Here, we show the controlled nucleation and motion of isolated three-fold vertices under an applied electric field. At the PbTiO3/SrRuO3 interface, a two-unit-cell thick SrTiO3 layer provides electrical boundary conditions for the formation of three-fold vertices. Utilizing the SrTiO3 layer and in situ electrical testing system, we find that isolated three-fold vertices can move in a controllable and reversible manner with a velocity up to ~629 nm s−1. Microstructural evolution of the nucleation and propagation of isolated three-fold vertices is further revealed by phase-field simulations. This work demonstrates the ability to electrically manipulate isolated three-fold vertices, shedding light on the dynamic property of isolated topological polar structures. Despite various known topological polar structures, the dynamic property of isolated ones is still poorly understood. Here, the authors show the controlled nucleation and ability to move of isolated three-fold vertices under an applied electric field.
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33
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Zhu R, Jiang Z, Zhang X, Zhong X, Tan C, Liu M, Sun Y, Li X, Qi R, Qu K, Liu Z, Wu M, Li M, Huang B, Xu Z, Wang J, Liu K, Gao P, Wang J, Li J, Bai X. Dynamics of Polar Skyrmion Bubbles under Electric Fields. PHYSICAL REVIEW LETTERS 2022; 129:107601. [PMID: 36112449 DOI: 10.1103/physrevlett.129.107601] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 06/23/2022] [Accepted: 08/11/2022] [Indexed: 06/15/2023]
Abstract
Room-temperature polar skyrmions, which have been recently discovered in oxide superlattice, have received considerable attention for their potential applications in nanoelectronics owing to their nanometer size, emergent chirality, and negative capacitance. For practical applications, their manipulation using external stimuli is a prerequisite. Herein, we study the dynamics of individual polar skyrmions at the nanoscale via in situ scanning transmission electron microscopy. By monitoring the electric-field-driven creation, annihilation, shrinkage, and expansion of topological structures in real space, we demonstrate the reversible transformation among skyrmion bubbles, elongated skyrmions, and monodomains. The underlying mechanism and interactions are discussed in conjunction with phase-field simulations. The electrical manipulation of nanoscale polar skyrmions allows the tuning of their dielectric permittivity at the atomic scale, and the detailed knowledge of their phase transition behaviors provides fundamentals for their applications in nanoelectronics.
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Affiliation(s)
- Ruixue Zhu
- Electron Microscopy Laboratory and International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Zhexin Jiang
- Department of Engineering Mechanics, Zhejiang University, Hangzhou 310027, Zhejiang, China
| | - Xinxin Zhang
- Electron Microscopy Laboratory and International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Xiangli Zhong
- School of Materials Science and Engineering, Xiangtan University, Xiangtan 411105, Hunan, China
| | - Congbing Tan
- Hunan Provincial Key Laboratory of Intelligent Sensors and Advanced Sensor Materials, School of Physics and Electronics, Hunan University of Science and Technology, Xiangtan 411201, Hunan, China
| | - Mingwei Liu
- Hunan Provincial Key Laboratory of Intelligent Sensors and Advanced Sensor Materials, School of Physics and Electronics, Hunan University of Science and Technology, Xiangtan 411201, Hunan, China
| | - Yuanwei Sun
- Electron Microscopy Laboratory and International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Xiaomei Li
- Electron Microscopy Laboratory and International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Ruishi Qi
- Electron Microscopy Laboratory and International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Ke Qu
- Electron Microscopy Laboratory and International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Zhetong Liu
- Electron Microscopy Laboratory and International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Mei Wu
- Electron Microscopy Laboratory and International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Mingqiang Li
- Electron Microscopy Laboratory and International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Boyuan Huang
- Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, Guangdong, China
| | - Zhi Xu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jinbin Wang
- School of Materials Science and Engineering, Xiangtan University, Xiangtan 411105, Hunan, China
| | - Kaihui Liu
- State Key Laboratory for Artificial Microstructure & Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
- Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, Beijing, 100871, China
| | - Peng Gao
- Electron Microscopy Laboratory and International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
- Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, Beijing, 100871, China
| | - Jie Wang
- Department of Engineering Mechanics, Zhejiang University, Hangzhou 310027, Zhejiang, China
- Zhejiang Laboratory, Hangzhou 311100, Zhejiang, China
| | - Jiangyu Li
- Guangdong Provincial Key Laboratory of Functional Oxide Materials and Devices, Southern University of Science and Technology, Shenzhen 518055, Guangdong, China
| | - Xuedong Bai
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
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34
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Guo X, Zhou L, Roul B, Wu Y, Huang Y, Das S, Hong Z. Theoretical Understanding of Polar Topological Phase Transitions in Functional Oxide Heterostructures: A Review. SMALL METHODS 2022; 6:e2200486. [PMID: 35900067 DOI: 10.1002/smtd.202200486] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 06/15/2022] [Indexed: 06/15/2023]
Abstract
The exotic topological phase is attracting considerable attention in condensed matter physics and materials science over the past few decades due to intriguing physical insights. As a combination of "topology" and "ferroelectricity," the ferroelectric (polar) topological structures are a fertile playground for emergent phenomena and functionalities with various potential applications. Herein, the review starts with the universal concept of the polar topological phase and goes on to briefly discuss the important role of computational tools such as phase-field simulations in designing polar topological phases in oxide heterostructures. In particular, the history of the development of phase-field simulations for ferroelectric oxide heterostructures is highlighted. Then, the current research progress of polar topological phases and their emergent phenomena in ferroelectric functional oxide heterostructures is reviewed from a theoretical perspective, including the topological polar structures, the establishment of phase diagrams, their switching kinetics and interconnections, phonon dynamics, and various macroscopic properties. Finally, this review offers a perspective on the future directions for the discovery of novel topological phases in other ferroelectric systems and device design for next-generation electronic device applications.
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Affiliation(s)
- Xiangwei Guo
- School of Materials Science and Engineering, Zhejiang University, Hangzhou, Zhejiang, 310027, China
- Institute of Advanced Semiconductors and Zhejiang Provincial Key Laboratory of Power Semiconductor Materials and Devices, Hangzhou Innovation Center, Zhejiang University, Hangzhou, Zhejiang, 311200, China
- Cyrus Tang Center for Sensor Materials and Applications, State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou, Zhejiang, 310027, China
| | - Linming Zhou
- School of Materials Science and Engineering, Zhejiang University, Hangzhou, Zhejiang, 310027, China
| | - Basanta Roul
- Materials Research Centre, Indian Institute of Science, Bangalore, 560012, India
- Central Research Laboratory, Bharat Electronics Limited, Bangalore, 560013, India
| | - Yongjun Wu
- School of Materials Science and Engineering, Zhejiang University, Hangzhou, Zhejiang, 310027, China
- Cyrus Tang Center for Sensor Materials and Applications, State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou, Zhejiang, 310027, China
| | - Yuhui Huang
- School of Materials Science and Engineering, Zhejiang University, Hangzhou, Zhejiang, 310027, China
| | - Sujit Das
- Materials Research Centre, Indian Institute of Science, Bangalore, 560012, India
| | - Zijian Hong
- School of Materials Science and Engineering, Zhejiang University, Hangzhou, Zhejiang, 310027, China
- Cyrus Tang Center for Sensor Materials and Applications, State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou, Zhejiang, 310027, China
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35
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Kavle P, Zorn JA, Dasgupta A, Wang B, Ramesh M, Chen LQ, Martin LW. Strain-Driven Mixed-Phase Domain Architectures and Topological Transitions in Pb 1- x Sr x TiO 3 Thin Films. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2203469. [PMID: 35917499 DOI: 10.1002/adma.202203469] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2022] [Revised: 07/08/2022] [Indexed: 06/15/2023]
Abstract
The potential for creating hierarchical domain structures, or mixtures of energetically degenerate phases with distinct patterns that can be modified continually, in ferroelectric thin films offers a pathway to control their mesoscale structure beyond lattice-mismatch strain with a substrate. Here, it is demonstrated that varying the strontium content provides deterministic strain-driven control of hierarchical domain structures in Pb1- x Srx TiO3 solid-solution thin films wherein two types, c/a and a1 /a2 , of nanodomains can coexist. Combining phase-field simulations, epitaxial thin-film growth, detailed structural, domain, and physical-property characterization, it is observed that the system undergoes a gradual transformation (with increasing strontium content) from droplet-like a1 /a2 domains in a c/a domain matrix, to a connected-labyrinth geometry of c/a domains, to a disconnected labyrinth structure of the same, and, finally, to droplet-like c/a domains in an a1 /a2 domain matrix. A relationship between the different mixed-phase modulation patterns and its topological nature is established. Annealing the connected-labyrinth structure leads to domain coarsening forming distinctive regions of parallel c/a and a1 /a2 domain stripes, offering additional design flexibility. Finally, it is found that the connected-labyrinth domain patterns exhibit the highest dielectric permittivity.
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Affiliation(s)
- Pravin Kavle
- Department of Materials Science and Engineering, University of California, Berkeley and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Jacob A Zorn
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Arvind Dasgupta
- Department of Materials Science and Engineering, University of California, Berkeley and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Bo Wang
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Maya Ramesh
- Department of Materials Science and Engineering, University of California, Berkeley and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Long-Qing Chen
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Lane W Martin
- Department of Materials Science and Engineering, University of California, Berkeley and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
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Linker T, Fukushima S, Kalia RK, Krishnamoorthy A, Nakano A, Nomura KI, Shimamura K, Shimojo F, Vashishta P. Towards computational polar-topotronics: Multiscale neural-network quantum molecular dynamics simulations of polar vortex states in SrTiO3/PbTiO3 nanowires. FRONTIERS IN NANOTECHNOLOGY 2022. [DOI: 10.3389/fnano.2022.884149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Recent discoveries of polar topological structures (e.g., skyrmions and merons) in ferroelectric/paraelectric heterostructures have opened a new field of polar topotronics. However, how complex interplay of photoexcitation, electric field and mechanical strain controls these topological structures remains elusive. To address this challenge, we have developed a computational approach at the nexus of machine learning and first-principles simulations. Our multiscale neural-network quantum molecular dynamics molecular mechanics approach achieves orders-of-magnitude faster computation, while maintaining quantum-mechanical accuracy for atoms within the region of interest. This approach has enabled us to investigate the dynamics of vortex states formed in PbTiO3 nanowires embedded in SrTiO3. We find topological switching of these vortex states to topologically trivial, uniformly polarized states using electric field and trivial domain-wall states using shear strain. These results, along with our earlier results on optical control of polar topology, suggest an exciting new avenue toward opto-electro-mechanical control of ultrafast, ultralow-power polar topotronic devices.
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37
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Physical realization of topological Roman surface by spin-induced ferroelectric polarization in cubic lattice. Nat Commun 2022; 13:2373. [PMID: 35501351 PMCID: PMC9061858 DOI: 10.1038/s41467-022-29764-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 03/24/2022] [Indexed: 11/08/2022] Open
Abstract
Topology, an important branch of mathematics, is an ideal theoretical tool to describe topological states and phase transitions. Many topological concepts have found their physical entities in real or reciprocal spaces identified by topological invariants, which are usually defined on orientable surfaces, such as torus and sphere. It is natural to investigate the possible physical realization of more intriguing non-orientable surfaces. Herein, we show that the set of spin-induced ferroelectric polarizations in cubic perovskite oxides AMn3Cr4O12 (A = La and Tb) reside on the topological Roman surface—a non-orientable two-dimensional manifold formed by sewing a Möbius strip edge to that of a disc. The induced polarization may travel in a loop along the non-orientable Möbius strip or orientable disc, depending on the spin evolution as controlled by an external magnetic field. Experimentally, the periodicity of polarization can be the same or twice that of the rotating magnetic field, which is consistent with the orientability of the disc and the Möbius strip, respectively. This path-dependent topological magnetoelectric effect presents a way to detect the global geometry of a surface and deepens our understanding of topology in both mathematics and physics. A non-orientable surface can mirror reflecting the man travelling on it. Realizing such topological object is fascinating. Here, the authors discover that antiferromagnetic-induced polarization in a solid can realize a non-orientable Roman surface.
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38
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Li Y, Zatterin E, Conroy M, Pylypets A, Borodavka F, Björling A, Groenendijk DJ, Lesne E, Clancy AJ, Hadjimichael M, Kepaptsoglou D, Ramasse QM, Caviglia AD, Hlinka J, Bangert U, Leake SJ, Zubko P. Electrostatically Driven Polarization Flop and Strain-Induced Curvature in Free-Standing Ferroelectric Superlattices. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2106826. [PMID: 35064954 DOI: 10.1002/adma.202106826] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Revised: 12/21/2021] [Indexed: 06/14/2023]
Abstract
The combination of strain and electrostatic engineering in epitaxial heterostructures of ferroelectric oxides offers many possibilities for inducing new phases, complex polar topologies, and enhanced electrical properties. However, the dominant effect of substrate clamping can also limit the electromechanical response and often leaves electrostatics to play a secondary role. Releasing the mechanical constraint imposed by the substrate can not only dramatically alter the balance between elastic and electrostatic forces, enabling them to compete on par with each other, but also activates new mechanical degrees of freedom, such as the macroscopic curvature of the heterostructure. In this work, an electrostatically driven transition from a predominantly out-of-plane polarized to an in-plane polarized state is observed when a PbTiO3 /SrTiO3 superlattice with a SrRuO3 bottom electrode is released from its substrate. In turn, this polarization rotation modifies the lattice parameter mismatch between the superlattice and the thin SrRuO3 layer, causing the heterostructure to curl up into microtubes. Through a combination of synchrotron-based scanning X-ray diffraction imaging, Raman scattering, piezoresponse force microscopy, and scanning transmission electron microscopy, the crystalline structure and domain patterns of the curved superlattices are investigated, revealing a strong anisotropy in the domain structure and a complex mechanism for strain accommodation.
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Affiliation(s)
- Yaqi Li
- Department of Physics and Astronomy, University College London, Gower Street, London, WC1E 6BT, UK
| | - Edoardo Zatterin
- Department of Physics and Astronomy, University College London, Gower Street, London, WC1E 6BT, UK
- ESRF, The European Synchrotron, 71 Avenue des Martyrs, Grenoble, 38000, France
| | - Michele Conroy
- Department of Materials, Imperial College London, Exhibition Road, London, SW7 2AZ, UK
- Department of Physics, Bernal Institute, University of Limerick, Limerick, V94 T9PX, Ireland
- London Centre for Nanotechnology, 17-19 Gordon Street, London, WC1H 0HA, UK
| | - Anastasiia Pylypets
- Institute of Physics of the Czech Academy of Sciences, Na Slovance 2, 18221 Praha 8, Czech Republic
| | - Fedir Borodavka
- Institute of Physics of the Czech Academy of Sciences, Na Slovance 2, 18221 Praha 8, Czech Republic
| | | | - Dirk J Groenendijk
- Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, Delft, GA 2600, The Netherlands
| | - Edouard Lesne
- Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, Delft, GA 2600, The Netherlands
| | - Adam J Clancy
- Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, UK
| | - Marios Hadjimichael
- Department of Quantum Matter Physics, University of Geneva, Geneva, 1211, Switzerland
| | - Demie Kepaptsoglou
- SuperSTEM Laboratory, SciTech Daresbury Campus, Daresbury, WA4 4AD, UK
- Department of Physics, University of York, York, YO10 5DD, UK
| | - Quentin M Ramasse
- SuperSTEM Laboratory, SciTech Daresbury Campus, Daresbury, WA4 4AD, UK
- Schools of Chemical and Process Engineering, & Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
| | - Andrea D Caviglia
- Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, Delft, GA 2600, The Netherlands
| | - Jiri Hlinka
- Institute of Physics of the Czech Academy of Sciences, Na Slovance 2, 18221 Praha 8, Czech Republic
| | - Ursel Bangert
- Department of Physics, Bernal Institute, University of Limerick, Limerick, V94 T9PX, Ireland
| | - Steven J Leake
- ESRF, The European Synchrotron, 71 Avenue des Martyrs, Grenoble, 38000, France
| | - Pavlo Zubko
- Department of Physics and Astronomy, University College London, Gower Street, London, WC1E 6BT, UK
- London Centre for Nanotechnology, 17-19 Gordon Street, London, WC1H 0HA, UK
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39
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Liu Y, Liu J, Pan H, Cheng X, Hong Z, Xu B, Chen LQ, Nan CW, Lin YH. Phase-Field Simulations of Tunable Polar Topologies in Lead-Free Ferroelectric/Paraelectric Multilayers with Ultrahigh Energy-Storage Performance. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2108772. [PMID: 35034410 DOI: 10.1002/adma.202108772] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 01/13/2022] [Indexed: 06/14/2023]
Abstract
Dielectric capacitors are emerging energy-storage components that require both high energy-storage density and high efficiency. The conventional approach to energy-storage enhancement is polar nanodomain engineering via chemical modification. Here, a new approach of domain engineering is proposed by exploiting the tunable polar topologies that have been observed recently in ferroelectric/paraelectric multilayer films. Using phase-field simulations, it is demonstrated that vortex, spiral, and in-plane polar structures can be stabilized in BiFeO3 /SrTiO3 (BFO/STO) multilayers by tailoring the strain state and layer thickness. Various switching dynamics are realized in these polar topologies, resulting in relaxor-ferroelectric-, antiferroelectric-, and paraelectric-like polarization behaviors, respectively. Ultrahigh energy-storage densities above 170 J cm-3 and efficiencies above 95% are achievable in STO/BFO/STO trilayers. This strategy should be generally implementable in other multilayer dielectrics and offers a new avenue to enhancing energy storage by tuning the polar topology and thus the polarization characteristics.
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Affiliation(s)
- Yiqian Liu
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, P. R. China
| | - Junfu Liu
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, P. R. China
| | - Hao Pan
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | | | - Zijian Hong
- Laboratory of Dielectric Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou, Zhejiang, 310027, P. R. China
| | - Ben Xu
- Graduate School of China Academy of Engineering Physics, Beijing, 100094, P. R. China
| | - Long-Qing Chen
- Department of Materials Science and Engineering and Materials Research Institute, The Pennsylvania State University, University Park, PA, 16802-5005, USA
| | - Ce-Wen Nan
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, P. R. China
| | - Yuan-Hua Lin
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, P. R. China
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Linker T, Nomura KI, Aditya A, Fukshima S, Kalia RK, Krishnamoorthy A, Nakano A, Rajak P, Shimmura K, Shimojo F, Vashishta P. Exploring far-from-equilibrium ultrafast polarization control in ferroelectric oxides with excited-state neural network quantum molecular dynamics. SCIENCE ADVANCES 2022; 8:eabk2625. [PMID: 35319991 PMCID: PMC8942355 DOI: 10.1126/sciadv.abk2625] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 01/31/2022] [Indexed: 06/14/2023]
Abstract
Ferroelectric materials exhibit a rich range of complex polar topologies, but their study under far-from-equilibrium optical excitation has been largely unexplored because of the difficulty in modeling the multiple spatiotemporal scales involved quantum-mechanically. To study optical excitation at spatiotemporal scales where these topologies emerge, we have performed multiscale excited-state neural network quantum molecular dynamics simulations that integrate quantum-mechanical description of electronic excitation and billion-atom machine learning molecular dynamics to describe ultrafast polarization control in an archetypal ferroelectric oxide, lead titanate. Far-from-equilibrium quantum simulations reveal a marked photo-induced change in the electronic energy landscape and resulting cross-over from ferroelectric to octahedral tilting topological dynamics within picoseconds. The coupling and frustration of these dynamics, in turn, create topological defects in the form of polar strings. The demonstrated nexus of multiscale quantum simulation and machine learning will boost not only the emerging field of ferroelectric topotronics but also broader optoelectronic applications.
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Affiliation(s)
- Thomas Linker
- Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, CA 90089-0242, USA
| | - Ken-ichi Nomura
- Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, CA 90089-0242, USA
| | - Anikeya Aditya
- Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, CA 90089-0242, USA
| | - Shogo Fukshima
- Department of Physics, Kumamoto University, Kumamoto 860-8555, Japan
| | - Rajiv K. Kalia
- Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, CA 90089-0242, USA
| | - Aravind Krishnamoorthy
- Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, CA 90089-0242, USA
| | - Aiichiro Nakano
- Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, CA 90089-0242, USA
| | - Pankaj Rajak
- Amazon, 410 Terry Ave. North, Seattle, WA 98109-5210 USA
| | - Kohei Shimmura
- Department of Physics, Kumamoto University, Kumamoto 860-8555, Japan
| | - Fuyuki Shimojo
- Department of Physics, Kumamoto University, Kumamoto 860-8555, Japan
| | - Priya Vashishta
- Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, CA 90089-0242, USA
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Abstract
Ferroelectric materials manifest unique dielectric, ferroelastic, and piezoelectric properties. A targeted design of ferroelectrics at the nanoscale is not only of fundamental appeal but holds the highest potential for applications. Compared to two-dimensional nanostructures such as thin films and superlattices, one-dimensional ferroelectric nanowires are investigated to a much lesser extent. Here, we reveal a variety of the topological polarization states, particularly the vortex and helical chiral phases, in loaded ferroelectric nanowires, which enable us to complete the strain–temperature phase diagram of the one-dimensional ferroelectrics. These phases are of prime importance for optoelectronics and quantum communication technologies.
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42
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O'Connell EN, Moore K, McFall E, Hennessy M, Moynihan E, Bangert U, Conroy M. TopoTEM: A Python Package for Quantifying and Visualizing Scanning Transmission Electron Microscopy Data of Polar Topologies. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2022; 28:1-9. [PMID: 35318910 DOI: 10.1017/s1431927622000435] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The exotic internal structure of polar topologies in multiferroic materials offers a rich landscape for materials science research. As the spatial scale of these entities is often subatomic in nature, aberration-corrected transmission electron microscopy (TEM) is the ideal characterization technique. Software to quantify and visualize the slight shifts in atomic placement within unit cells is of paramount importance due to the now routine acquisition of images at such resolution. In the previous ~decade since the commercialization of aberration-corrected TEM, many research groups have written their own code to visualize these polar entities. More recently, open-access Python packages have been developed for the purpose of TEM atomic position quantification. Building on these packages, we introduce the TEMUL Toolkit: a Python package for analysis and visualization of atomic resolution images. Here, we focus specifically on the TopoTEM module of the toolkit where we show an easy to follow, streamlined version of calculating the atomic displacements relative to the surrounding lattice and thus plotting polarization. We hope this toolkit will benefit the rapidly expanding field of topology-based nano-electronic and quantum materials research, and we invite the electron microscopy community to contribute to this open-access project.
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Affiliation(s)
- Eoghan N O'Connell
- Department of Physics, Bernal Institute, University of Limerick, Limerick, Ireland
| | - Kalani Moore
- Department of Physics, Bernal Institute, University of Limerick, Limerick, Ireland
| | - Elora McFall
- Department of Physics, Bernal Institute, University of Limerick, Limerick, Ireland
| | - Michael Hennessy
- Department of Physics, Bernal Institute, University of Limerick, Limerick, Ireland
| | - Eoin Moynihan
- Department of Physics, Bernal Institute, University of Limerick, Limerick, Ireland
| | - Ursel Bangert
- Department of Physics, Bernal Institute, University of Limerick, Limerick, Ireland
| | - Michele Conroy
- Department of Physics, Bernal Institute, University of Limerick, Limerick, Ireland
- Department of Materials, Faculty of Engineering, London Centre of Nanotechnology, Imperial College London, London, UK
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43
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High-density switchable skyrmion-like polar nanodomains integrated on silicon. Nature 2022; 603:63-67. [PMID: 35236971 DOI: 10.1038/s41586-021-04338-w] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Accepted: 12/10/2021] [Indexed: 11/08/2022]
Abstract
Topological domains in ferroelectrics1-5 have received much attention recently owing to their novel functionalities and potential applications6,7 in electronic devices. So far, however, such topological polar structures have been observed only in superlattices grown on oxide substrates, which limits their applications in silicon-based electronics. Here we report the realization of room-temperature skyrmion-like polar nanodomains in lead titanate/strontium titanate bilayers transferred onto silicon. Moreover, an external electric field can reversibly switch these nanodomains into the other type of polar texture, which substantially modifies their resistive behaviours. The polar-configuration-modulated resistance is ascribed to the distinct band bending and charge carrier distribution in the core of the two types of polar texture. The integration of high-density (more than 200 gigabits per square inch) switchable skyrmion-like polar nanodomains on silicon may enable non-volatile memory applications using topological polar structures in oxides.
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Gong FH, Chen YT, Zhu YL, Tang YL, Zhang H, Wang YJ, Wu B, Liu JQ, Shi TT, Yang LX, Li CJ, Feng YP, Ma XL. Thickness-Dependent Polar Domain Evolution in Strained, Ultrathin PbTiO 3 Films. ACS APPLIED MATERIALS & INTERFACES 2022; 14:9724-9733. [PMID: 35138804 DOI: 10.1021/acsami.1c20797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Ferroelectric ultrathin films have great potential in electronic devices and device miniaturization with the innovation of technology. In the process of product commercialization, understanding the domain evolution and topological properties of ferroelectrics is a prerequisite for high-density storage devices. In this work, a series of ultrathin PbTiO3 (PTO) films with varying thicknesses were deposited on cubic KTaO3 substrates by pulsed laser deposition and were researched by Cs-corrected scanning transmission electron microscopy (STEM), reciprocal space mapping (RSM), and piezoresponse force microscopy (PFM). RSM experiments indicate the existence of a/c domains and show that the lattice constant varies continuously, which is further confirmed by atomic-scale STEM imaging. Diffraction contrast analysis clarifies that with the decrease in PTO film thickness, the critical thickness for the formation of a/c domains could be missing. When the thickness of PTO films is less than 6 nm, the domain configurations in the ultrathin PTO films are the coexistence of a/c domains and bowl-like topological structures, where the latter ones were identified as convergent and divergent types of meron. In addition, abundant 90° charged domain walls in these ultrathin PTO films were identified. PFM studies reveal clear ferroelectric properties for these ultrathin PTO films. These results may shed light on further understanding the domain evolution and topological properties in ultrathin ferroelectric PTO films.
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Affiliation(s)
- Feng-Hui Gong
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
- School of Materials Science and Engineering, University of Science and Technology of China, Wenhua Road 72, Shenyang 110016, China
| | - Yu-Ting Chen
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
- School of Materials Science and Engineering, University of Science and Technology of China, Wenhua Road 72, Shenyang 110016, China
| | - Yin-Lian Zhu
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
- Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan 523808, Guangdong, China
| | - Yun-Long Tang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
| | - Heng Zhang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
- School of Materials Science and Engineering, University of Science and Technology of China, Wenhua Road 72, Shenyang 110016, China
| | - Yu-Jia Wang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
| | - Bo Wu
- Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan 523808, Guangdong, China
| | - Jia-Qi Liu
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
- School of Materials Science and Engineering, University of Science and Technology of China, Wenhua Road 72, Shenyang 110016, China
| | - Tong-Tong Shi
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
- School of Materials Science and Engineering, University of Science and Technology of China, Wenhua Road 72, Shenyang 110016, China
| | - Li-Xin Yang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
| | - Chang-Ji Li
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
| | - Yan-Peng Feng
- Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan 523808, Guangdong, China
| | - Xiu-Liang Ma
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
- State Key Lab of Advanced Processing and Recycling on Non-ferrous Metals, Lanzhou University of Technology, Langongping Road 287, Lanzhou 730050, China
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45
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Behera P, May MA, Gómez-Ortiz F, Susarla S, Das S, Nelson CT, Caretta L, Hsu SL, McCarter MR, Savitzky BH, Barnard ES, Raja A, Hong Z, García-Fernandez P, Lovesey SW, van der Laan G, Ercius P, Ophus C, Martin LW, Junquera J, Raschke MB, Ramesh R. Electric field control of chirality. SCIENCE ADVANCES 2022; 8:eabj8030. [PMID: 34985953 PMCID: PMC8730600 DOI: 10.1126/sciadv.abj8030] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Polar textures have attracted substantial attention in recent years as a promising analog to spin-based textures in ferromagnets. Here, using optical second-harmonic generation–based circular dichroism, we demonstrate deterministic and reversible control of chirality over mesoscale regions in ferroelectric vortices using an applied electric field. The microscopic origins of the chirality, the pathway during the switching, and the mechanism for electric field control are described theoretically via phase-field modeling and second-principles simulations, and experimentally by examination of the microscopic response of the vortices under an applied field. The emergence of chirality from the combination of nonchiral materials and subsequent control of the handedness with an electric field has far-reaching implications for new electronics based on chirality as a field-controllable order parameter.
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Affiliation(s)
- Piush Behera
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Molly A. May
- Department of Physics, Department of Chemistry and JILA, University of Colorado, Boulder, CO 80309, USA
| | - Fernando Gómez-Ortiz
- Departmento de Ciencias de la Tierra y Física de la Materia Condensada, Universidad de Cantabria, Cantabria Campus Internacional, 39005 Santander, Spain
| | - Sandhya Susarla
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Sujit Das
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Christopher T. Nelson
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Lucas Caretta
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Shang-Lin Hsu
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Margaret R. McCarter
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Benjamin H. Savitzky
- National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Edward S. Barnard
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Archana Raja
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Zijian Hong
- School of Materials Science and Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Pablo García-Fernandez
- Departmento de Ciencias de la Tierra y Física de la Materia Condensada, Universidad de Cantabria, Cantabria Campus Internacional, 39005 Santander, Spain
| | - Stephen W. Lovesey
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK
| | - Gerrit van der Laan
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK
| | - Peter Ercius
- National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Colin Ophus
- National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Lane W. Martin
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Javier Junquera
- Departmento de Ciencias de la Tierra y Física de la Materia Condensada, Universidad de Cantabria, Cantabria Campus Internacional, 39005 Santander, Spain
- Corresponding author. (R.R.); (J.J.)
| | - Markus B. Raschke
- Department of Physics, Department of Chemistry and JILA, University of Colorado, Boulder, CO 80309, USA
| | - Ramamoorthy Ramesh
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA
- Corresponding author. (R.R.); (J.J.)
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46
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Feng YP, Jiang RJ, Zhu YL, Tang YL, Wang YJ, Zou MJ, Geng WR, Ma XL. Strain coupling of ferroelastic domains and misfit dislocations in [101]-oriented ferroelectric PbTiO 3 films. RSC Adv 2022; 12:20423-20431. [PMID: 35919158 PMCID: PMC9280779 DOI: 10.1039/d2ra03584g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 06/30/2022] [Indexed: 12/02/2022] Open
Abstract
High-index perovskite ferroelectric thin films possess excellent dielectric permittivity, piezoelectric coefficient, and exotic ferroelectric switching properties. They also exhibit complications in the ferroelastic domains, misfit dislocations, and strain-relaxation behaviors. Exploring the relationship of the ferroelastic domains and misfit dislocations may be of benefit for promoting the high-quality growth of these thin films. Here, the strain field of the ferroelastic domains and misfit dislocations in [101]-oriented PbTiO3/(La, Sr)(Al, Ta)O3 epitaxial thin films were investigated by advanced aberration-corrected (scanning) transmission electron microscopy (TEM) combined with geometry phase analysis (GPA). Two types of misfit dislocations with projected Burgers vectors of a[001] or a[100] on the (010) plane were elucidated, whose strain fields included in-plane strain and lattice rotation coupled with the c domains above them. Besides, it was demonstrated that the coupling was kept inside the PbTiO3 films when the film thickness was increased. Furthermore, the polarization rotation was observed in both narrow c domains and around the misfit dislocation cores, which may be attributed to the flexoelectric effect. These results are expected to provide useful information for understanding the nucleation and propagation mechanism of ferroelastic domains and for further modifying the growth of high-index ferroelectric thin films. The strain coupling of misfit dislocations and ferroelastic domains is revealed in [101]-oriented PbTiO3/(La, Sr)(Al, Ta)O3 films and flexoelectric-induced polarization rotation is observed around the misfit dislocation cores.![]()
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Affiliation(s)
- Y. P. Feng
- Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - R. J. Jiang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
- School of Materials Science and Engineering, University of Science and Technology of China, Wenhua Road 72, Shenyang 110016, China
| | - Y. L. Zhu
- Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Y. L. Tang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
| | - Y. J. Wang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
| | - M. J. Zou
- Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - W. R. Geng
- Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - X. L. Ma
- Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- State Key Lab of Advanced Processing and Recycling on Non-ferrous Metals, Lanzhou University of Technology, Langongping Road 287, Lanzhou 730050, China
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47
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Geng W, Wang Y, Tang Y, Zhu Y, Wu B, Yang L, Feng Y, Zou M, Ma X. Atomic-Scale Tunable Flexoelectric Couplings in Oxide Multiferroics. NANO LETTERS 2021; 21:9601-9608. [PMID: 34766784 DOI: 10.1021/acs.nanolett.1c03352] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Flexoelectricity is an effective tool in modulating the crystallographic structures and properties of oxides for multifunctional applications. However, engineering the nonuniform strain to obtain tunable flexoelectric behaviors at the atomic scale remains an ongoing challenge in conventional substrate-imposed ferroelectric films. Here, the regulatable flexoelectric behaviors are demonstrated at atomic scale in [110]-oriented BiFeO3 thin films, which are triggered by the strain-field coupling of high-density interfacial dislocations. Using aberration-corrected scanning transmission electron microscopy, the asymmetric polarization rotation around the single dislocation is revealed, which is induced by the gradient strain fields of the single dislocation. These strain fields are highly correlated to generate huge strain gradients between neighboring dislocations, and thereby, serial flexoelectric responses are engineered as a function of dislocation spacings in thicker BiFeO3 films. This work opens a pathway for the modulation of flexoelectric responses in ferroelectrics, which could be extended to other functional materials to create exotic phenomena.
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Affiliation(s)
- Wanrong Geng
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Yujia Wang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, 110016 Shenyang, China
| | - Yunlong Tang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, 110016 Shenyang, China
| | - Yinlian Zhu
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, 110016 Shenyang, China
| | - Bo Wu
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Lixin Yang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, 110016 Shenyang, China
| | - Yanpeng Feng
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Minjie Zou
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Xiuliang Ma
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, 110016 Shenyang, China
- State Key Lab of Advanced Processing and Recycling on Non-ferrous Metals, Lanzhou University of Technology, Langongping Road 287, 730050 Lanzhou, China
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48
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Spontaneous helielectric nematic liquid crystals: Electric analog to helimagnets. Proc Natl Acad Sci U S A 2021; 118:2111101118. [PMID: 34642251 DOI: 10.1073/pnas.2111101118] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/12/2021] [Indexed: 11/18/2022] Open
Abstract
Recently, a type of ferroelectric nematic fluid has been discovered in liquid crystals in which the molecular polar nature at molecule level is amplified to macroscopic scales through a ferroelectric packing of rod-shaped molecules. Here, we report on the experimental proof of a polar chiral liquid matter state, dubbed helielectric nematic, stabilized by the local polar ordering coupled to the chiral helicity. This helielectric structure carries the polar vector rotating helically, analogous to the magnetic counterpart of helimagnet. The helielectric state can be retained down to room temperature and demonstrates gigantic dielectric and nonlinear optical responses. This matter state opens a new chapter for developing the diverse polar liquid crystal devices.
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49
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Zhang Y, Yu R, Zhu J. Displacement separation analysis from atomic-resolution images. Ultramicroscopy 2021; 232:113404. [PMID: 34656896 DOI: 10.1016/j.ultramic.2021.113404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 09/26/2021] [Accepted: 10/03/2021] [Indexed: 11/16/2022]
Abstract
Structural distortions frequently occur in materials, either periodically (ferroelectric or antiferroelectric) or in local areas (domain boundaries, surfaces/interfaces, dislocations). Measuring atomic displacements from an average lattice is of crucial importance for analyzing structural distortions and their connections to physical properties. Conventionally, the displacements are measured atom-by-atom by fitting atomic-resolution images with two-dimensional gaussian functions. Here, we exhibit an efficient method, named Displacement Separation Analysis, DSA in short, to directly separate atomic displacements from an average lattice based on Fourier space filtering. Using antiferroelectric AgNbO3 as a model system, we demonstrate the consistence between DSA and gaussian fitting. The suppression of polarization at interfacial region of h-LuFeO3/α-Al2O3 heterostructure and the emergence of modulation structure in LuFe2O4+x is then revealed using DSA, attesting the implication of DSA in unveiling structural distortions either locally or periodically. Inspired by the simple principle of DSA, such method can be used for any atomic-resolution images, including TEM, STM, and AFM images to exhibit the atomic displacement intuitively.
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Affiliation(s)
- Yang Zhang
- National Center for Electron Microscopy in Beijing, Key Laboratory of Advanced Materials (MOE), The State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, P.R. China; Ji Hua Laboratory, Foshan, 528299, P.R. China; State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, P.R. China
| | - Rong Yu
- National Center for Electron Microscopy in Beijing, Key Laboratory of Advanced Materials (MOE), The State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, P.R. China.
| | - Jing Zhu
- National Center for Electron Microscopy in Beijing, Key Laboratory of Advanced Materials (MOE), The State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, P.R. China.
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50
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Shimada T, Wang Y, Hamaguchi T, Kasai K, Masuda K, Van Lich L, Xu T, Wang J, Hirakata H. Emergence of non-trivial polar topologies hidden in singular stress field in SrTiO 3: topological strain-field engineering. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:505301. [PMID: 34547728 DOI: 10.1088/1361-648x/ac28c1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 09/21/2021] [Indexed: 06/13/2023]
Abstract
Discovery of non-trivial topological structures in condensed matters holds promise in novel technological paradigms. In contrast to ferromagnetics, where a variety of topological structures such as vortex, meron, and skyrmion have been discovered, only few topological structures can exist in ferroelectrics due to the lack of non-collinear interaction like the Dzyaloshinskii-Moriya interaction in ferromagnetics. Here, we demonstrate that polarization structures with a wide range of topological numbers (winding numbernfrom -3 to +1) can be mechanically excited and designed by the mode-I singular stress field formed near the crack-tip in incipient ferroelectric SrTiO3. Our phase-field simulations based on Ginzburg-Landau theory successfully reveals that the near-tip polar topology is driven by the flexoelectric coupling with intense strain gradient at the tip, while a variety of the far-field topological structures is triggered by a collaboration between the electrostrictive and flexoelectric effects. The strain (gradient) field analysis further shows that the unexpected topological characters are implied in the singular stress field, which develops a variety of polar topologies near the crack tip. Therefore, our work provides a novel insight into the unusual interplay between mechanical- and ferroelectric-topologies, i.e. 'topological strain-field engineering', which paves the way to the mechanical design of functional topologies in the matter.
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Affiliation(s)
- Takahiro Shimada
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
| | - Yu Wang
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
| | - Takayuki Hamaguchi
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
| | - Kohta Kasai
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
| | - Kairi Masuda
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
| | - Le Van Lich
- School of Materials Science and Engineering, Hanoi University of Science and Technology, No 1, Dai Co Viet Street, Hanoi 100000, Vietnam
| | - Tao Xu
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, People's Republic of China
| | - Jie Wang
- Department of Engineering Mechanics & Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, School of Aeronautics and Astronautics, Zhejiang University, Hangzhou 310027, People's Republic of China
| | - Hiroyuki Hirakata
- Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan
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