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Zhu R, Zheng S, Li X, Wang T, Tan C, Yu T, Liu Z, Wang X, Li J, Wang J, Gao P. Atomic-Scale Tracking Topological Phase Transition Dynamics of Polar Vortex-Antivortex Pairs. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024:e2312072. [PMID: 38734889 DOI: 10.1002/adma.202312072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 04/02/2024] [Indexed: 05/13/2024]
Abstract
Non-trivial topological structures, such as vortex-antivortex (V-AV) pairs, have garnered significant attention in the field of condensed matter physics. However, the detailed topological phase transition dynamics of V-AV pairs, encompassing behaviors like self-annihilation, motion, and dissociation, have remained elusive in real space. Here, polar V-AV pairs are employed as a model system, and their transition pathways are tracked with atomic-scale resolution, facilitated by in situ (scanning) transmission electron microscopy and phase field simulations. This investigation reveals that polar vortices and antivortices can stably coexist as bound pairs at room temperature, and their polarization decreases with heating. No dissociation behavior is observed between the V-AV phase at room temperature and the paraelectric phase at high temperature. However, the application of electric fields can promote the approach of vortex and antivortex cores, ultimately leading to their annihilation near the interface. Revealing the transition process mediated by polar V-AV pairs at the atomic scale, particularly the role of polar antivortex, provides new insights into understanding the topological phases of matter and their topological phase transitions. Moreover, the detailed exploration of the dynamics of polar V-AV pairs under thermal and electrical fields lays a solid foundation for their potential applications in electronic devices.
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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
| | - Sizheng Zheng
- Department of Engineering Mechanics, Zhejiang University, Hangzhou, Zhejiang, 310027, China
| | - Xiaomei Li
- Electron Microscopy Laboratory, and International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871, China
- School of Integrated Circuits, East China Normal University, Shanghai, 200241, China
| | - Tao Wang
- Electron Microscopy Laboratory, and International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871, 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, Hunan, 411201, China
| | - Tiancheng Yu
- 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
| | - Xinqiang Wang
- State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing, 100871, China
- Collaborative Innovation Centre of Quantum Matter, Beijing, 100871, China
| | - Jiangyu Li
- Guangdong Provincial Key Laboratory of Functional Oxide Materials and Devices, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
- Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Jie Wang
- Department of Engineering Mechanics, Zhejiang University, Hangzhou, Zhejiang, 310027, China
- Zhejiang Laboratory, Hangzhou, 311100, China
| | - Peng Gao
- Electron Microscopy Laboratory, and International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871, China
- Collaborative Innovation Centre of Quantum Matter, Beijing, 100871, China
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2
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Wang JH, Zhu MX, Li YS, Chen SJ, Gong FH, Lv XD, Jiang RJ, Liu SZ, Li C, Wang YJ, Tang YL, Zhu YL, Ma XL. Large Polarization Near 50 μC/cm 2 in a Single Unit Cell Layer SrTiO 3. NANO LETTERS 2024; 24:4082-4090. [PMID: 38526914 DOI: 10.1021/acs.nanolett.3c04695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/27/2024]
Abstract
The generally nonpolar SrTiO3 has attracted more attention recently because of its possibly induced novel polar states and related paraelectric-ferroelectric phase transitions. By using controlled pulsed laser deposition, high-quality, ultrathin, and strained SrTiO3 layers were obtained. Here, transmission electron microscopy and theoretical simulations have unveiled highly polar states in SrTiO3 films even down to one unit cell at room temperature, which were stabilized in the PbTiO3/SrTiO3/PbTiO3 sandwich structures by in-plane tensile strain and interfacial coupling, as evidenced by large tetragonality (∼1.05), notable polar ion displacement (0.019 nm), and thus ultrahigh spontaneous polarization (up to ∼50 μC/cm2). These values are nearly comparable to those of the strong ferroelectrics as the PbZrxTi1-xO3 family. Our findings provide an effective and practical approach for integrating large strain states into oxide films and inducing polarization in nonpolar materials, which may broaden the functionality of nonpolar oxides and pave the way for the discovery of new electronic materials.
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Affiliation(s)
- Jing-Hui Wang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
- School of Materials Science and Engineering, University of Science and Technology of China, Shenyang 110016, China
| | - Mei-Xiong Zhu
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
- School of Materials Science and Engineering, University of Science and Technology of China, Shenyang 110016, China
| | - Yu-Shu Li
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
- School of Materials Science and Engineering, University of Science and Technology of China, Shenyang 110016, China
| | - Shuang-Jie Chen
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
- School of Materials Science and Engineering, University of Science and Technology of China, Shenyang 110016, China
| | - Feng-Hui Gong
- Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan 523808, China
| | - Xiao-Dong Lv
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
- School of Materials Science and Engineering, University of Science and Technology of China, Shenyang 110016, China
| | - Ru-Jian Jiang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
- School of Materials Science and Engineering, University of Science and Technology of China, Shenyang 110016, China
| | - Su-Zhen Liu
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
- School of Materials Science and Engineering, University of Science and Technology of China, Shenyang 110016, China
| | - Changji Li
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
| | - Yu-Jia Wang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
| | - Yun-Long Tang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
- School of Materials Science and Engineering, University of Science and Technology of China, Shenyang 110016, China
| | - Yin-Lian Zhu
- Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan 523808, China
- School of Materials Science and Engineering, Hunan University of Science and Technology, Xiangtan 411201, 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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3
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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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4
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Jiang W, Wang S, Yang X, Yang J. Effect of Aspect Ratio of Ferroelectric Nanofilms on Polarization Vortex Stability under Uniaxial Tension or Compression. MATERIALS (BASEL, SWITZERLAND) 2023; 16:7699. [PMID: 38138840 PMCID: PMC10744852 DOI: 10.3390/ma16247699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 11/30/2023] [Accepted: 12/12/2023] [Indexed: 12/24/2023]
Abstract
Mastering the variations in the stability of a polarization vortex is fundamental for the development of ferroelectric devices based on polarization vortex domain structures. Some phase field simulations were conducted on PbTiO3 nanofilms with an initial polarization vortex under uniaxial tension or compression to investigate the conditions of vortex instability and the effects of aspect ratio of nanofilms and temperature on them. The instability of a polarization vortex is strongly dependent on aspect ratio and temperature. The critical compressive stress increases with decreasing aspect ratio under the action of compressive stress. However, the critical tensile stress first decreases and then increases with decreasing aspect ratio, then continues to decrease. There are two inflection points in the curve. In addition, an elevated temperature makes both the critical tensile and compressive stresses decline, and will also cause the aspect ratio corresponding to the inflection point to decrease. These are very important for the design of promising nano-ferroelectric devices based on polarization vortices to improve their performance while maintaining storage density.
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Affiliation(s)
- Wenkai Jiang
- School of Mechanical Engineering, Wuhan Polytechnic University, Wuhan 430048, China; (W.J.)
| | - Sen Wang
- School of Mechanical Engineering, Wuhan Polytechnic University, Wuhan 430048, China; (W.J.)
| | - Xinhua Yang
- School of Transportation, Civil Engineering and Architecture, Foshan University, Foshan 528200, China;
| | - Junsheng Yang
- School of Mechanical Engineering, Wuhan Polytechnic University, Wuhan 430048, China; (W.J.)
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5
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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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6
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Addiego C, Zorn JA, Gao W, Das S, Guo J, Qu C, Zhao L, Martin LW, Ramesh R, Chen LQ, Pan X. Multiscale Electric-Field Imaging of Polarization Vortex Structures in PbTiO3/SrTiO3 Superlattices. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2023; 29:1620-1621. [PMID: 37613804 DOI: 10.1093/micmic/ozad067.832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Affiliation(s)
- Christopher Addiego
- Department of Physics and Astronomy, University of California, Irvine, CA, United States
| | - Jacob A Zorn
- Department of Materials Science and Engineering and Materials Research Institute, The Pennsylvania State University, University Park, PA, United States
| | - Wenpei Gao
- Department of Materials Science and Engineering, University of California, Irvine, CA, United States
| | - Sujit Das
- Department of Materials Science and Engineering, University of California, Berkeley, CA, United States
| | - Jiaqi Guo
- Department of Physics and Astronomy, University of California, Irvine, CA, United States
| | - Chengqing Qu
- Department of Physics and Astronomy, University of California, Irvine, CA, United States
| | - Liming Zhao
- Department of Physics and Astronomy, University of California, Irvine, CA, United States
| | - Lane W Martin
- Department of Materials Science and Engineering, University of California, Berkeley, CA, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Ramamoorthy Ramesh
- Department of Materials Science and Engineering, University of California, Berkeley, CA, United States
| | - Long-Qing Chen
- Department of Materials Science and Engineering and Materials Research Institute, The Pennsylvania State University, University Park, PA, United States
| | - Xiaoqing Pan
- Department of Physics and Astronomy, University of California, Irvine, CA, United States
- Department of Materials Science and Engineering, University of California, Irvine, CA, United States
- Irvine Materials Research Institute, University of California, Irvine, CA, United States
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7
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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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8
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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: 3] [Impact Index Per Article: 3.0] [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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9
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A small-dataset-trained deep learning framework for identifying atoms on transmission electron microscopy images. Sci Rep 2023; 13:2631. [PMID: 36788257 PMCID: PMC9929221 DOI: 10.1038/s41598-023-29606-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Accepted: 02/07/2023] [Indexed: 02/16/2023] Open
Abstract
To accurately identify atoms on noisy transmission electron microscope images, a deep learning (DL) approach is employed to estimate the map of probabilities at each pixel for being an atom with element discernment. Thanks to a delicately-designed loss function and the ability to extract features, the proposed DL networks can be trained by a small dataset created from approximately 30 experimental images, each with a size of 256 × 256 pixels2. The accuracy and robustness of the network were verified by resolving the structural defects of graphene and polar structures in PbTiO3/SrTiO3 multilayers from both the general TEM images and their imitated images on which intensities of some pixels lost randomly. Such a network has the potential to identify atoms from very few images of beam-sensitive material and explosive images recorded in a dynamical atomic process. The idea of using a small-dataset-trained DL framework to resolve a specific problem may prove instructive for practical DL applications in various fields.
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10
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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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11
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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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12
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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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13
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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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14
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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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15
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Dai C, Stoica VA, Das S, Hong Z, Martin LW, Ramesh R, Freeland JW, Wen H, Gopalan V, Chen LQ. Tunable Nanoscale Evolution and Topological Phase Transitions of a Polar Vortex Supercrystal. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2106401. [PMID: 34958699 DOI: 10.1002/adma.202106401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 12/03/2021] [Indexed: 06/14/2023]
Abstract
Understanding the phase transitions and domain evolutions of mesoscale topological structures in ferroic materials is critical to realizing their potential applications in next-generation high-performance storage devices. Here, the behaviors of a mesoscale supercrystal are studied with 3D nanoscale periodicity and rotational topology phases in a PbTiO3 /SrTiO3 (PTO/STO) superlattice under thermal and electrical stimuli using a combination of phase-field simulations and X-ray diffraction experiments. A phase diagram of temperature versus polar state is constructed, showing the formation of the supercrystal from a mixed vortex and a-twin state and a temperature-dependent erasing process of a supercrystal returning to a classical a-twin structure. Under an in-plane electric field bias at room temperature, the vortex topology of the supercrystal irreversibly transforms to a new type of stripe-like supercrystal. Under an out-of-plane electric field, the vortices inside the supercrystal undergo a topological phase transition to polar skyrmions. These results demonstrate the potential for the on-demand manipulation of polar topology and transformations in supercrystals using electric fields. The findings provide a theoretical understanding that may be utilized to guide the design and control of mesoscale polar structures and to explore novel polar structures in other systems and their topological nature.
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Affiliation(s)
- Cheng Dai
- Department of Materials Science and Engineering and Materials Research Institute, Pennsylvania State University, University Park, PA, 16802, USA
| | - Vladimir Alexandru Stoica
- Department of Materials Science and Engineering and Materials Research Institute, Pennsylvania State University, University Park, PA, 16802, USA
- Advanced Photon Source, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - Sujit Das
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - Zijian Hong
- Lab of Dielectric Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Lane W Martin
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Ramamoorthy Ramesh
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | - John W Freeland
- Advanced Photon Source, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - Haidan Wen
- Advanced Photon Source, Argonne National Laboratory, Argonne, IL, 60439, USA
- Materials Science Division, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - Venkatraman Gopalan
- Department of Materials Science and Engineering and Materials Research Institute, Pennsylvania State University, University Park, PA, 16802, USA
| | - Long-Qing Chen
- Department of Materials Science and Engineering and Materials Research Institute, Pennsylvania State University, University Park, PA, 16802, USA
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16
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Moore K, O’Connell EN, Griffin SM, Downing C, Colfer L, Schmidt M, Nicolosi V, Bangert U, Keeney L, Conroy M. Charged Domain Wall and Polar Vortex Topologies in a Room-Temperature Magnetoelectric Multiferroic Thin Film. ACS APPLIED MATERIALS & INTERFACES 2022; 14:5525-5536. [PMID: 35044754 PMCID: PMC8815039 DOI: 10.1021/acsami.1c17383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 01/09/2022] [Indexed: 06/14/2023]
Abstract
Multiferroic topologies are an emerging solution for future low-power magnetic nanoelectronics due to their combined tuneable functionality and mobility. Here, we show that in addition to being magnetoelectric multiferroic at room temperature, thin-film Aurivillius phase Bi6TixFeyMnzO18 is an ideal material platform for both domain wall and vortex topology-based nanoelectronic devices. Utilizing atomic-resolution electron microscopy, we reveal the presence and structure of 180°-type charged head-to-head and tail-to-tail domain walls passing throughout the thin film. Theoretical calculations confirm the subunit cell cation site preference and charged domain wall energetics for Bi6TixFeyMnzO18. Finally, we show that polar vortex-type topologies also form at out-of-phase boundaries of stacking faults when internal strain and electrostatic energy gradients are altered. This study could pave the way for controlled polar vortex topology formation via strain engineering in other multiferroic thin films. Moreover, these results confirm that the subunit cell topological features play an important role in controlling the charge and spin state of Aurivillius phase films and other multiferroic heterostructures.
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Affiliation(s)
- Kalani Moore
- Department
of Physics, Bernal Institute, School of Natural Sciences, University of Limerick, Limerick V94 T9PX, Ireland
| | - Eoghan N. O’Connell
- Department
of Physics, Bernal Institute, School of Natural Sciences, University of Limerick, Limerick V94 T9PX, Ireland
| | - Sinéad M. Griffin
- Materials
Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
- Molecular
Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Clive Downing
- Advanced
Microscopy Laboratory & AMBER, Trinity
College Dublin, Dublin D02 PN40, Ireland
| | - Louise Colfer
- Tyndall
National Institute, University College Cork, Cork T12 R5CP, Ireland
| | - Michael Schmidt
- Tyndall
National Institute, University College Cork, Cork T12 R5CP, Ireland
| | - Valeria Nicolosi
- Advanced
Microscopy Laboratory & AMBER, Trinity
College Dublin, Dublin D02 PN40, Ireland
- School of
Chemistry, Trinity College Dublin, Dublin D02 PN40, Ireland
| | - Ursel Bangert
- Department
of Physics, Bernal Institute, School of Natural Sciences, University of Limerick, Limerick V94 T9PX, Ireland
| | - Lynette Keeney
- Tyndall
National Institute, University College Cork, Cork T12 R5CP, Ireland
| | - Michele Conroy
- Department
of Physics, Bernal Institute, School of Natural Sciences, University of Limerick, Limerick V94 T9PX, Ireland
- Department
of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, U.K.
- London
Centre for Nanotechnology, Imperial College
London, Exhibition Road, London SW7 2AZ, U.K.
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17
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Grünebohm A, Marathe M, Khachaturyan R, Schiedung R, Lupascu DC, Shvartsman VV. Interplay of domain structure and phase transitions: theory, experiment and functionality. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 34:073002. [PMID: 34731841 DOI: 10.1088/1361-648x/ac3607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 11/03/2021] [Indexed: 06/13/2023]
Abstract
Domain walls and phase boundaries are fundamental ingredients of ferroelectrics and strongly influence their functional properties. Although both interfaces have been studied for decades, often only a phenomenological macroscopic understanding has been established. The recent developments in experiments and theory allow to address the relevant time and length scales and revisit nucleation, phase propagation and the coupling of domains and phase transitions. This review attempts to specify regularities of domain formation and evolution at ferroelectric transitions and give an overview on unusual polar topological structures that appear as transient states and at the nanoscale. We survey the benefits, validity, and limitations of experimental tools as well as simulation methods to study phase and domain interfaces. We focus on the recent success of these tools in joint scale-bridging studies to solve long lasting puzzles in the field and give an outlook on recent trends in superlattices.
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Affiliation(s)
- Anna Grünebohm
- Interdisciplinary Centre for Advanced Materials Simulations (ICAMS), Ruhr-University Bochum, 44801 Bochum, Germany
| | - Madhura Marathe
- Interdisciplinary Centre for Advanced Materials Simulations (ICAMS), Ruhr-University Bochum, 44801 Bochum, Germany
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, 08193 Bellaterra, Spain
- Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Ruben Khachaturyan
- Interdisciplinary Centre for Advanced Materials Simulations (ICAMS), Ruhr-University Bochum, 44801 Bochum, Germany
| | - Raphael Schiedung
- Interdisciplinary Centre for Advanced Materials Simulations (ICAMS), Ruhr-University Bochum, 44801 Bochum, Germany
- National Institute for Material Science (NIMS), Tsukuba 305-0047, Japan
| | - Doru C Lupascu
- Institute for Materials Science and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, 45141 Essen, Germany
| | - Vladimir V Shvartsman
- Institute for Materials Science and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, 45141 Essen, Germany
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18
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Yang Y, Wu M, Zheng X, Zheng C, Xu J, Xu Z, Li X, Lou X, Wu D, Liu X, Pennycook SJ, Wen Z. Atomic-scale fatigue mechanism of ferroelectric tunnel junctions. SCIENCE ADVANCES 2021; 7:eabh2716. [PMID: 34818041 PMCID: PMC8612688 DOI: 10.1126/sciadv.abh2716] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 10/05/2021] [Indexed: 06/13/2023]
Abstract
Ferroelectric tunnel junctions (FTJs) are promising candidates for next-generation memories due to fast read/write speeds and low-power consumptions. Here, we investigate resistance fatigue of FTJs, which is performed on Pt/BaTiO3/Nb:SrTiO3 devices. By direct observations of the 5–unit cell–thick BaTiO3 barrier with high-angle annular dark-field imaging and electron energy loss spectroscopy, oxygen vacancies are found to aggregate at the Pt/BaTiO3 interface during repetitive switching, leading to a ferroelectric dead layer preventing domain nucleation and growth. Severe oxygen deficiency also makes BaTiO3 lattices energetically unfavorable and lastly induces a destruction of local perovskite structure of the barrier. Ferroelectric properties are thus degraded, which reduces barrier contrast between ON and OFF states and smears electroresistance characteristics of Pt/BaTiO3/Nb:SrTiO3 FTJs. These results reveal an atomic-scale fatigue mechanism of ultrathin ferroelectric barriers associated with the aggregation of charged defects, facilitating the design of reliable FTJs and ferroelectric nanoelectronic devices for practical applications.
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Affiliation(s)
- Yihao Yang
- College of Physics and Center for Marine Observation and Communications, Qingdao University, Qingdao 266071, China
| | - Ming Wu
- State Key Laboratory of Electrical Insulation and Power Equipment and Frontier Institute of Science and Technology, Xi’an Jiaotong University, Xi’an 710049, China
- Department of Materials Science and Engineering, National University of Singapore, Singapore 117575, Singapore
| | - Xingwen Zheng
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Ji’nan 250100, China
| | - Chunyan Zheng
- College of Physics and Center for Marine Observation and Communications, Qingdao University, Qingdao 266071, China
| | - Jibo Xu
- College of Physics and Center for Marine Observation and Communications, Qingdao University, Qingdao 266071, China
| | - Zhiyu Xu
- College of Physics and Center for Marine Observation and Communications, Qingdao University, Qingdao 266071, China
| | - Xiaofei Li
- College of Physics and Center for Marine Observation and Communications, Qingdao University, Qingdao 266071, China
| | - Xiaojie Lou
- State Key Laboratory of Electrical Insulation and Power Equipment and Frontier Institute of Science and Technology, Xi’an Jiaotong University, Xi’an 710049, China
| | - Di Wu
- National Laboratory of Solid State Microstructures, Department of Materials Science and Engineering, Jiangsu Key Laboratory of Artificial Functional Materials and Collaborative Innovation Center for Advanced Materials, Nanjing University, Nanjing 210093, China
| | - Xiaohui Liu
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Ji’nan 250100, China
| | - Stephen J. Pennycook
- Department of Materials Science and Engineering, National University of Singapore, Singapore 117575, Singapore
| | - Zheng Wen
- College of Physics and Center for Marine Observation and Communications, Qingdao University, Qingdao 266071, China
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19
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Susarla S, García-Fernández P, Ophus C, Das S, Aguado-Puente P, McCarter M, Ercius P, Martin LW, Ramesh R, Junquera J. Atomic scale crystal field mapping of polar vortices in oxide superlattices. Nat Commun 2021; 12:6273. [PMID: 34725320 PMCID: PMC8560910 DOI: 10.1038/s41467-021-26476-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 09/22/2021] [Indexed: 11/10/2022] Open
Abstract
Polar vortices in oxide superlattices exhibit complex polarization topologies. Using a combination of electron energy loss near-edge structure analysis, crystal field multiplet theory, and first-principles calculations, we probe the electronic structure within such polar vortices in [(PbTiO3)16/(SrTiO3)16] superlattices at the atomic scale. The peaks in Ti [Formula: see text]-edge spectra shift systematically depending on the position of the Ti4+ cations within the vortices i.e., the direction and magnitude of the local dipole. First-principles computation of the local projected density of states on the Ti [Formula: see text] orbitals, together with the simulated crystal field multiplet spectra derived from first principles are in good agreement with the experiments.
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Affiliation(s)
- Sandhya Susarla
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA. .,Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA. .,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
| | - Pablo García-Fernández
- Departamento de Ciencias de la Tierra y Física de la Materia Condensada, Universidad de Cantabria, Cantabria Campus Internacional, Avenida de los Castros s/n, 39005, Santander, Spain
| | - Colin Ophus
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Sujit Das
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
| | | | - Margaret McCarter
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Peter Ercius
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Lane W Martin
- Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Ramamoorthy Ramesh
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA. .,Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA. .,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA. .,Department of Physics, University of California, Berkeley, CA, 94720, USA.
| | - Javier Junquera
- Departamento de Ciencias de la Tierra y Física de la Materia Condensada, Universidad de Cantabria, Cantabria Campus Internacional, Avenida de los Castros s/n, 39005, Santander, Spain.
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20
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Mun J, Peng W, Roh CJ, Lee S, Matsumura S, Lee JS, Noh TW, Kim M. In Situ Cryogenic HAADF-STEM Observation of Spontaneous Transition of Ferroelectric Polarization Domain Structures at Low Temperatures. NANO LETTERS 2021; 21:8679-8686. [PMID: 34644077 DOI: 10.1021/acs.nanolett.1c02729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Precise determination of atomic structures in ferroelectric thin films and their evolution with temperature is crucial for fundamental study and design of functional materials. However, this has been impeded by the lack of techniques applicable to a thin-film geometry. Here we use cryogenic scanning transmission electron microscopy (STEM) to observe the atomic structure of a BaTiO3 film on a (111)-SrTiO3 substrate under varying temperatures. Our study explicitly proves a structure transition from a complex polymorphic nanodomain configuration at room temperature transitioning to a homogeneous ground-state rhombohedral structure of BaTiO3 below ∼250 K, which was predicted by phase-field simulation. More importantly, another unexpected transition is revealed, a transition to complex nanodomains below ∼105 K caused by an altered mechanical boundary condition due to the antiferrodistortive phase transition of the SrTiO3 substrate. This study demonstrates the power of cryogenic STEM in elucidating structure-property relationships in numerous functional materials at low temperatures.
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Affiliation(s)
- Junsik Mun
- Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea
- Department of Materials Science and Engineering and Research Institute of Advanced Materials, Seoul National University, Seoul 08826, Republic of Korea
| | - Wei Peng
- Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea
- Department of Physics and Astronomy, Seoul National University, Seoul 08826, Republic of Korea
| | - Chang Jae Roh
- Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea
- Department of Physics and Astronomy, Seoul National University, Seoul 08826, Republic of Korea
- Department of Physics and Photon Science, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea
| | - Sangmin Lee
- Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea
- Department of Materials Science and Engineering and Research Institute of Advanced Materials, Seoul National University, Seoul 08826, Republic of Korea
| | - Syo Matsumura
- Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Fukuoka 819-0395, Japan
| | - Jong Seok Lee
- Department of Physics and Photon Science, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea
| | - Tae Won Noh
- Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea
- Department of Physics and Astronomy, Seoul National University, Seoul 08826, Republic of Korea
| | - Miyoung Kim
- Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea
- Department of Materials Science and Engineering and Research Institute of Advanced Materials, Seoul National University, Seoul 08826, Republic of Korea
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21
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Magnetoelectric phase transition driven by interfacial-engineered Dzyaloshinskii-Moriya interaction. Nat Commun 2021; 12:5453. [PMID: 34526513 PMCID: PMC8443571 DOI: 10.1038/s41467-021-25759-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Accepted: 08/23/2021] [Indexed: 11/09/2022] Open
Abstract
Strongly correlated oxides with a broken symmetry could exhibit various phase transitions, such as superconductivity, magnetism and ferroelectricity. Construction of superlattices using these materials is effective to design crystal symmetries at atomic scale for emergent orderings and phases. Here, antiferromagnetic Ruddlesden-Popper Sr2IrO4 and perovskite paraelectric (ferroelectric) SrTiO3 (BaTiO3) are selected to epitaxially fabricate superlattices for symmetry engineering. An emergent magnetoelectric phase transition is achieved in Sr2IrO4/SrTiO3 superlattices with artificially designed ferroelectricity, where an observable interfacial Dzyaloshinskii-Moriya interaction driven by non-equivalent interface is considered as the microscopic origin. By further increasing the polarization namely interfacial Dzyaloshinskii-Moriya interaction via replacing SrTiO3 with BaTiO3, the transition temperature can be enhanced from 46 K to 203 K, accompanying a pronounced magnetoelectric coefficient of ~495 mV/cm·Oe. This interfacial engineering of Dzyaloshinskii-Moriya interaction provides a strategy to design quantum phases and orderings in correlated electron systems.
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22
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Tan C, Dong Y, Sun Y, Liu C, Chen P, Zhong X, Zhu R, Liu M, Zhang J, Wang J, Liu K, Bai X, Yu D, Ouyang X, Wang J, Gao P, Luo Z, Li J. Engineering polar vortex from topologically trivial domain architecture. Nat Commun 2021; 12:4620. [PMID: 34330915 PMCID: PMC8324780 DOI: 10.1038/s41467-021-24922-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 07/15/2021] [Indexed: 11/08/2022] Open
Abstract
Topologically nontrivial polar structures are not only attractive for high-density data storage, but also for ultralow power microelectronics thanks to their exotic negative capacitance. The vast majority of polar structures emerging naturally in ferroelectrics, however, are topologically trivial, and there are enormous interests in artificially engineered polar structures possessing nontrivial topology. Here we demonstrate reconstruction of topologically trivial strip-like domain architecture into arrays of polar vortex in (PbTiO3)10/(SrTiO3)10 superlattice, accomplished by fabricating a cross-sectional lamella from the superlattice film. Using a combination of techniques for polarization mapping, atomic imaging, and three-dimensional structure visualization supported by phase field simulations, we reveal that the reconstruction relieves biaxial epitaxial strain in thin film into a uniaxial one in lamella, changing the subtle electrostatic and elastostatic energetics and providing the driving force for the polar vortex formation. The work establishes a realistic strategy for engineering polar topologies in otherwise ordinary ferroelectric superlattices.
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Affiliation(s)
- 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, Hunan, China
- School of Materials Science and Engineering, Xiangtan University, Xiangtan, Hunan, China
- Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Yongqi Dong
- Shenzhen Key Laboratory of Nanobiomechanics, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, China
| | - Yuanwei Sun
- International Center for Quantum Materials, Peking University, Beijing, China
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing, China
| | - Chang Liu
- Department of Engineering Mechanics, School of Aeronautics and Astronautics, Zhejiang University, Hangzhou, Zhejiang, China
- Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province, School of Mechanics and Engineering, Southwest Jiaotong University, Chengdu, Sichuan, China
| | - Pan Chen
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Xiangli Zhong
- School of Materials Science and Engineering, Xiangtan University, Xiangtan, Hunan, China
| | - Ruixue Zhu
- International Center for Quantum Materials, Peking University, Beijing, China
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing, 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, Hunan, China
| | - Jingmin Zhang
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing, China
| | - Jinbin Wang
- School of Materials Science and Engineering, Xiangtan University, Xiangtan, Hunan, China
| | - Kaihui Liu
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing, China
- Collaborative Innovation Centre of Quantum Matter, Beijing, China
| | - Xuedong Bai
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Dapeng Yu
- Collaborative Innovation Centre of Quantum Matter, Beijing, China
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing, China
- Shenzhen Key Laboratory of Quantum Science and Engineering, Shenzhen, Guangdong, China
| | - Xiaoping Ouyang
- School of Materials Science and Engineering, Xiangtan University, Xiangtan, Hunan, China
| | - Jie Wang
- Department of Engineering Mechanics, School of Aeronautics and Astronautics, Zhejiang University, Hangzhou, Zhejiang, China.
- Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, Zhejiang University, Hangzhou, Zhejiang, China.
| | - Peng Gao
- International Center for Quantum Materials, Peking University, Beijing, China.
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing, China.
- Collaborative Innovation Centre of Quantum Matter, Beijing, China.
- Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, Beijing, China.
| | - Zhenlin Luo
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, China.
| | - Jiangyu Li
- Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China.
- Shenzhen Key Laboratory of Nanobiomechanics, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China.
- Guangdong Provincial Key Laboratory of Functional Oxide Materials and Devices, Southern University of Science and Technology, Shenzhen, Guangdong, China.
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23
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Tang Y, Zhu Y, Wu B, Wang Y, Yang L, Feng Y, Zou M, Geng W, Ma X. Periodic Polarization Waves in a Strained, Highly Polar Ultrathin SrTiO 3. NANO LETTERS 2021; 21:6274-6281. [PMID: 34252283 DOI: 10.1021/acs.nanolett.1c02117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
SrTiO3 is generally paraelectric with centrosymmetric structure exhibiting unique quantum fluctuation related ferroelectricity. Here we reveal highly polar and periodic polarization waves in SrTiO3 at room temperature, which is stabilized by periodic tensile strains in a sandwiched PbTiO3/SrTiO3/PbTiO3 structure. Scanning transmission electron microscopy reveals that periodic a/c domain structures in PbTiO3 layers exert unique periodic tensile strains in the ultrathin SrTiO3 layer and consequently make the highly polar and periodic states of SrTiO3. The as-received polar SrTiO3 layer features peak polar ion displacement of ∼0.01 nm and peak tetragonality of ∼1.07. These peak values are larger than previous results, which are comparable to that of bulk ferroelectric PbTiO3. Our results suggest that it is possible to integrate large and periodic strain state in oxide films with exotic properties, which in turn could be useful in optical applications and information addressing when used as memory unit.
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Affiliation(s)
- Yunlong Tang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, 110016 Shenyang, China
| | - Yinlian Zhu
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, 110016 Shenyang, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Bo Wu
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Yujia Wang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, 110016 Shenyang, 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
| | - Wanrong Geng
- 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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24
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Gong FH, Tang YL, Zhu YL, Zhang H, Wang YJ, Chen YT, Feng YP, Zou MJ, Wu B, Geng WR, Cao Y, Ma XL. Atomic mapping of periodic dipole waves in ferroelectric oxide. SCIENCE ADVANCES 2021; 7:eabg5503. [PMID: 34244147 PMCID: PMC8270497 DOI: 10.1126/sciadv.abg5503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 05/27/2021] [Indexed: 05/02/2023]
Abstract
A dipole wave is composed of head-to-tail connected electric dipoles in the form of sine function. Potential applications in information carrying, transporting, and processing are expected, and logic circuits based on nonlinear wave interaction are promising for dipole waves. Although similar spin waves are well known in ferromagnetic materials for their roles in some physical essence, electric dipole wave behavior and even its existence in ferroelectric materials are still elusive. Here, we observe the atomic morphology of large-scale dipole waves in PbTiO3/SrTiO3 superlattice mediated by tensile epitaxial strains on scandate substrates. The dipole waves can be expressed in the formula of y = Asin (2πx/L) + y 0, where the wave amplitude (A) and wavelength (L) correspond to 1.5 and 6.6 nm, respectively. This study suggests that by engineering strain at the nanoscale, it should be possible to fabricate unknown polar textures, which could facilitate the development of nanoscale ferroelectric devices.
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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
| | - Yin-Lian Zhu
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China.
- Songshan Lake Materials Laboratory, Dongguan 523808, Guangdong, 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
| | - 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
| | - Yan-Peng Feng
- Songshan Lake Materials Laboratory, Dongguan 523808, Guangdong, China
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Min-Jie Zou
- Songshan Lake Materials Laboratory, Dongguan 523808, Guangdong, China
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Bo Wu
- Songshan Lake Materials Laboratory, Dongguan 523808, Guangdong, China
| | - Wan-Rong Geng
- Songshan Lake Materials Laboratory, Dongguan 523808, Guangdong, China
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Yi Cao
- 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
| | - 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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25
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Abid AY, Sun Y, Hou X, Tan C, Zhong X, Zhu R, Chen H, Qu K, Li Y, Wu M, Zhang J, Wang J, Liu K, Bai X, Yu D, Ouyang X, Wang J, Li J, Gao P. Creating polar antivortex in PbTiO 3/SrTiO 3 superlattice. Nat Commun 2021; 12:2054. [PMID: 33824335 PMCID: PMC8024303 DOI: 10.1038/s41467-021-22356-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 03/14/2021] [Indexed: 11/19/2022] Open
Abstract
Nontrivial topological structures offer a rich playground in condensed matters and promise alternative device configurations for post-Moore electronics. While recently a number of polar topologies have been discovered in confined ferroelectric PbTiO3 within artificially engineered PbTiO3/SrTiO3 superlattices, little attention was paid to possible topological polar structures in SrTiO3. Here we successfully create previously unrealized polar antivortices within the SrTiO3 of PbTiO3/SrTiO3 superlattices, accomplished by carefully engineering their thicknesses guided by phase-field simulation. Field- and thermal-induced Kosterlitz-Thouless-like topological phase transitions have also been demonstrated, and it was discovered that the driving force for antivortex formation is electrostatic instead of elastic. This work completes an important missing link in polar topologies, expands the reaches of topological structures, and offers insight into searching and manipulating polar textures.
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Grants
- JCYJ20200109115219157, JCYJ20170818163902553 Shenzhen Science and Technology Innovation Commission
- LZ17A020001 Natural Science Foundation of Zhejiang Province (Zhejiang Provincial Natural Science Foundation)
- 51672007, 11974023, 11875229, 51872251, 11972320, 11672264 and 92066203 National Natural Science Foundation of China (National Science Foundation of China)
- National Key R&D Program of China (2016YFA0300804, 2016YFA0201001, 2016YFA0300903) National Equipment Program of China (ZDYZ2015-1) Key R&D Program of Guangdong Province (2018B030327001, 2018B010109009, 2019B010931001) "2011 Program" Peking-Tsinghua-IOP Collaborative Innovation Center for Quantum Matter
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Affiliation(s)
- Adeel Y Abid
- International Center for Quantum Materials, Peking University, Beijing, China
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing, China
| | - Yuanwei Sun
- International Center for Quantum Materials, Peking University, Beijing, China
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing, China
| | - Xu Hou
- Department of Engineering Mechanics, School of Aeronautics and Astronautics, Zhejiang University, Hangzhou, China
| | - Congbing Tan
- School of Materials Science and Engineering, Xiangtan University, Xiangtan, Hunan, China
- Hunan Provincial Key Laboratory of Intelligent Sensors and Advanced Sensor Materials, School of Physics and Electronics, Hunan University of Science and Technology, Xiangtan, Hunan, China
| | - Xiangli Zhong
- School of Materials Science and Engineering, Xiangtan University, Xiangtan, Hunan, China.
| | - Ruixue Zhu
- International Center for Quantum Materials, Peking University, Beijing, China
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing, China
| | - Haoyun Chen
- Department of Engineering Mechanics, School of Aeronautics and Astronautics, Zhejiang University, Hangzhou, China
| | - Ke Qu
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing, China
- Shenzhen Key Laboratory of Nanobiomechanics, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China
| | - Yuehui Li
- International Center for Quantum Materials, Peking University, Beijing, China
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing, China
| | - Mei Wu
- International Center for Quantum Materials, Peking University, Beijing, China
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing, China
| | - Jingmin Zhang
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing, China
| | - Jinbin Wang
- School of Materials Science and Engineering, Xiangtan University, Xiangtan, Hunan, China
| | - Kaihui Liu
- Collaborative Innovation Centre of Quantum Matter, Beijing, China
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing, China
| | - Xuedong Bai
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Dapeng Yu
- Collaborative Innovation Centre of Quantum Matter, Beijing, China
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing, China
- Shenzhen Key Laboratory of Quantum Science and Engineering, Shenzhen, China
| | - Xiaoping Ouyang
- School of Materials Science and Engineering, Xiangtan University, Xiangtan, Hunan, China
| | - Jie Wang
- Department of Engineering Mechanics, School of Aeronautics and Astronautics, Zhejiang University, Hangzhou, China.
- Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, Zhejiang University, Hangzhou, China.
| | - Jiangyu Li
- Shenzhen Key Laboratory of Nanobiomechanics, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China.
- Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China.
- Guangdong Provincial Key Laboratory of Functional Oxide Materials and Devices, Southern University of Science and Technology, Shenzhen, Guangdong, China.
| | - Peng Gao
- International Center for Quantum Materials, Peking University, Beijing, China.
- Electron Microscopy Laboratory, School of Physics, Peking University, Beijing, China.
- Collaborative Innovation Centre of Quantum Matter, Beijing, China.
- Interdisciplinary Institute of Light-Element Quantum Materials and Research Center for Light-Element Advanced Materials, Peking University, Beijing, China.
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26
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Falsi L, Aversa M, Di Mei F, Pierangeli D, Xin F, Agranat AJ, DelRe E. Direct Observation of Fractal-Dimensional Percolation in the 3D Cluster Dynamics of a Ferroelectric Supercrystal. PHYSICAL REVIEW LETTERS 2021; 126:037601. [PMID: 33543979 DOI: 10.1103/physrevlett.126.037601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 12/07/2020] [Indexed: 06/12/2023]
Abstract
We perform percolation analysis of crossed-polarizer transmission images in a biased nanodisordered bulk KTN:Li perovskite. Two distinct percolative transitions are identified at two electric field thresholds. The low-field transition involves a directional fractal chain of dimension D=1.65, while the high-field transition has a dimension D>2. Direct cluster imaging in the volume is achieved using high-resolution orthographic 3D projections based on giant refraction. Percolation is attributed to a full-3D domain reorientation that mediates the transition from a ferroelectric supercrystal state to a disordered domain mosaic.
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Affiliation(s)
- Ludovica Falsi
- Dipartimento di Fisica, Università di Roma "La Sapienza," 00185 Rome, Italy
- Dipartimento S.B.A.I., Sezione di Fisica, "Sapienza" Università di Roma, I-00161 Roma, Italy
| | - Marco Aversa
- Dipartimento di Fisica, Università di Roma "La Sapienza," 00185 Rome, Italy
| | - Fabrizio Di Mei
- Dipartimento di Fisica, Università di Roma "La Sapienza," 00185 Rome, Italy
| | - Davide Pierangeli
- Dipartimento di Fisica, Università di Roma "La Sapienza," 00185 Rome, Italy
| | - Feifei Xin
- Dipartimento di Fisica, Università di Roma "La Sapienza," 00185 Rome, Italy
- College of Physics and Materials Science, Tianjin Normal University, 300387 Tianjin, China
| | - Aharon J Agranat
- The Brojde Center for Innovative Engineering and Computer Science, The Hebrew University, Jerusalem 91904, Israel
| | - Eugenio DelRe
- Dipartimento di Fisica, Università di Roma "La Sapienza," 00185 Rome, Italy
- ISC-CNR, Università di Roma "La Sapienza," 00185 Rome, Italy
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27
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Baker JS, Bowler DR. Polar Morphologies from First Principles: PbTiO
3
Films on SrTiO
3
Substrates and the p(2×Λ) Surface Reconstruction. ADVANCED THEORY AND SIMULATIONS 2020. [DOI: 10.1002/adts.202000154] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Jack S. Baker
- London Centre for Nanotechnology UCL 17‐19 Gordon St London WC1H 0AH UK
- Department of Physics & Astronomy UCL Gower St London WC1E 6BT UK
| | - David R. Bowler
- London Centre for Nanotechnology UCL 17‐19 Gordon St London WC1H 0AH UK
- Department of Physics & Astronomy UCL Gower St London WC1E 6BT UK
- International Centre for Materials Nanoarchitectonics (MANA) National Institute for Materials Science (NIMS) 1‐1 Namiki Tsukuba Ibaraki 305‐0044 Japan
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28
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Atomic-scale observations of electrical and mechanical manipulation of topological polar flux closure. Proc Natl Acad Sci U S A 2020; 117:18954-18961. [PMID: 32709747 PMCID: PMC7430988 DOI: 10.1073/pnas.2007248117] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Flux-closures, stable topological polar structures of nanometer size, are considered to be promising candidates as elements of future nanoelectronic and electromechanical devices. Understanding their phase transition pathways under external stimuli is therefore of vital importance for these potential applications. Here, using an atomically resolved in situ electron microscopy technique, we track the evolutions of the polarization of the flux-closure structure under both electric and stress fields with atomic resolution. We find that the flux-closure can be reversibly and controllably manipulated between the topological and ordinary ferroelectric states, enabling potential applications in electromechanical and nanoelectronic devices. The ability to controllably manipulate complex topological polar configurations such as polar flux-closures via external stimuli may allow the construction of new electromechanical and nanoelectronic devices. Here, using atomically resolved in situ scanning transmission electron microscopy, we find that the polar flux-closures in PbTiO3/SrTiO3 superlattice films are mobile and can be reversibly switched to ordinary single ferroelectric c or a domains under an applied electric field or stress. Specifically, the electric field initially drives movement of a flux-closure via domain wall motion and then breaks it to form intermediate a/c striped domains, whereas mechanical stress first squeezes the core of a flux-closure toward the interface and then form a/c domains with disappearance of the core. After removal of the external stimulus, the flux-closure structure spontaneously recovers. These observations can be precisely reproduced by phase field simulations, which also reveal the evolutions of the competing energies during phase transitions. Such reversible switching between flux-closures and ordinary ferroelectric states provides a foundation for potential electromechanical and nanoelectronic applications.
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