1
|
Han X, Zheng F, Frauenheim T, Zhao P, Liang Y. An elemental ferroelectric topological insulator in ψ-bismuthene. Phys Chem Chem Phys 2024; 26:26622-26627. [PMID: 39400558 DOI: 10.1039/d4cp03456b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2024]
Abstract
A ferroelectric quantum spin Hall insulator (FEQSHI) exhibits coexisting ferroelectricity and time-reversal symmetry protected edge states, holding exciting prospects for inviting both scientific and application advances, particularly in two-dimensional systems. However, FEQSHI candidates that consist of only one constituent element are rarely reported. Here, we show that ψ-bismuthene, an allotrope of bilayer Bi (110), is a concrete example of a two-dimensional elemental FEQSHI. It is demonstrated that ψ-bismuthene possesses measurable ferroelectric polarization and nontrivial band gap with moderate switching barrier, making it highly suitable for the detection and observation of ferroelectric topologically insulating states. Additionally, the auxetic behavior, quantum transport properties and ferroelectric controllable persistent spin helix in ψ-bismuthene are also discussed. These findings make ψ-bismuthene promising for both fundamental physics and technological innovations.
Collapse
Affiliation(s)
- Xuening Han
- College of Physics and Optoelectronic Engineering, Faculty of Information Science and Engineering, Ocean University of China, Songling Road 238, Qingdao 266100, People's Republic of China.
| | - Fulu Zheng
- Bremen Center for Computational Materials Science, University of Bremen, 28359 Bremen, Germany.
| | | | - Pei Zhao
- College of Physics and Optoelectronic Engineering, Faculty of Information Science and Engineering, Ocean University of China, Songling Road 238, Qingdao 266100, People's Republic of China.
| | - Yan Liang
- College of Physics and Optoelectronic Engineering, Faculty of Information Science and Engineering, Ocean University of China, Songling Road 238, Qingdao 266100, People's Republic of China.
| |
Collapse
|
2
|
Gao H, Liu Z, Gong Y, Ke C, Guo N, Wu J, Zeng X, Guo J, Li S, Cheng Z, Li J, Zhu H, Zhang LZ, Liu X, Liu S, Xie L, Zheng Q. Picometer-Level In Situ Manipulation of Ferroelectric Polarization in Van der Waals layered InSe. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024:e2404628. [PMID: 39367557 DOI: 10.1002/adma.202404628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2024] [Revised: 09/26/2024] [Indexed: 10/06/2024]
Abstract
Ferroelectric 2D van der Waals (vdW) layered materials are attracting increasing attention due to their potential applications in next-generation nanoelectronics and in-memory computing with polarization-dependent functionalities. Despite the critical role of polarization in governing ferroelectricity behaviors, its origin and relation with local structures in 2D vdW layered materials have not been fully elucidated so far. Here, intralayer sliding of approximately six degrees within each quadruple-layer of the prototype 2D vdW ferroelectrics InSe is directly observed and manipulated using sub-angstrom resolution imaging and in situ biasing in an aberration-corrected scanning transmission electron microscope. The in situ electric manipulation further indicates that the reversal of intralayer sliding can be achieved by altering the electric field direction. Density functional theory calculations reveal that the reversible picometer-level intralayer sliding is responsible for switchable out-of-plane polarization. The observation and manipulation of intralayer sliding demonstrate the structural origin of ferroelectricity in InSe and establish a dynamic structural variation model for future investigations on more 2D ferroelectric materials.
Collapse
Affiliation(s)
- Hanbin Gao
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing, 100190, China
| | - Ziyuan Liu
- Laboratory of Theoretical and Computational Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, China
| | - Yue Gong
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing, 100190, China
| | - Changming Ke
- Department of Physics, School of Science and Research Center for Industries of the Future, Westlake University, Hangzhou, Zhejiang, 310030, China
- Institute of Natural Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, 310024, China
| | - Ning Guo
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing, 100190, China
| | - Juanxia Wu
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing, 100190, China
| | - Xin Zeng
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing, 100190, China
| | - Jianfeng Guo
- Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Songyang Li
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Department of Physics, Renmin University of China, Beijing, 100872, China
| | - Zhihai Cheng
- Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Department of Physics, Renmin University of China, Beijing, 100872, China
| | - Jiawei Li
- School of Materials Science and Engineering, Tsinghua University, Beijing, 100190, China
| | - Hongwei Zhu
- School of Materials Science and Engineering, Tsinghua University, Beijing, 100190, China
| | - Li-Zhi Zhang
- Laboratory of Theoretical and Computational Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, China
| | - Xinfeng Liu
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing, 100190, China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Shi Liu
- Department of Physics, School of Science and Research Center for Industries of the Future, Westlake University, Hangzhou, Zhejiang, 310030, China
- Institute of Natural Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, 310024, China
| | - Liming Xie
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing, 100190, China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Qiang Zheng
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing, 100190, China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| |
Collapse
|
3
|
Feng Y, Dai Y, Huang B, Ma Y. Sliding Ferroelectricity Engineered Coupling between Spin Hall Effect and Layertronics in 2D Lattice. J Phys Chem Lett 2024; 15:6699-6704. [PMID: 38900495 DOI: 10.1021/acs.jpclett.4c01479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Coupling the spin Hall effect with novel degrees of freedom of electrons is central to the rich phenomena observed in condensed-matter physics. Here, using symmetry analysis and a low-energy k·p model, we report the sliding ferroelectricity engineered coupling between spin Hall effect and emerging layertronics, thereby generating the layer spin Hall effect (LSHE), in a 2D lattice. The physics is rooted in a pair of T-symmetry connected valleys, which experience spin splitting accompanied by large Berry curvature under spin-orbit coupling. The interaction between the out-of-plane ferroelectricity and electronic properties gives rise to the layer-locked Berry curvature and thus layer-polarized spin Hall effect (LP-SHE) in the bilayers. Such LP-SHE is strongly coupled with sliding ferroelectricity, enabling it to be ferroelectrically reversible. Using first-principles calculations, the mechanism is further demonstrated in a series of real bilayer systems, including MoS2, MoTe2, WSe2, MoSi2P4, and MoSi2As4. These phenomena and insights open a new direction for spin Hall effect.
Collapse
Affiliation(s)
- Yangyang Feng
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Shandanan Street 27, Jinan 250100, China
| | - Ying Dai
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Shandanan Street 27, Jinan 250100, China
| | - Baibiao Huang
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Shandanan Street 27, Jinan 250100, China
| | - Yandong Ma
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Shandanan Street 27, Jinan 250100, China
| |
Collapse
|
4
|
Huang J, Ke C, Qian Z, Liu S. Competing Charge Transfer and Screening Effects in Two-Dimensional Ferroelectric Capacitors. NANO LETTERS 2024; 24:6683-6688. [PMID: 38767925 DOI: 10.1021/acs.nanolett.4c01362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Two-dimensional (2D) ferroelectrics promise ultrathin flexible nanoelectronics, typically utilizing a metal-ferroelectric-metal sandwich structure. Electrodes can either contribute free carriers to screen the depolarization field, enhancing nanoscale ferroelectricity, or induce charge doping, disrupting the long-range crystalline order. We explore electrodes' dual roles in 2D ferroelectric capacitors, supported by first-principles calculations covering a range of electrode work functions. Our results reveal volcano-type relationships between ferroelectric-electrode binding affinity and work function, which are further unified by a quadratic scaling between the binding energy and the transferred interfacial charge. At the monolayer limit, charge transfer dictates the ferroelectric stability and switching properties. This general characteristic is confirmed in various 2D ferroelectrics including α-In2Se3, CuInP2S6, and SnTe. As the ferroelectric layer's thickness increases, the capacitor stability evolves from a charge-transfer-dominated state to a screening-dominated state. The delicate interplay between these two effects has important implications for 2D ferroelectric capacitor applications.
Collapse
Affiliation(s)
- Jiawei Huang
- Key Laboratory for Quantum Materials of Zhejiang Province, Department of Physics, School of Science, Westlake University, Hangzhou, Zhejiang 310030, China
| | - Changming Ke
- Key Laboratory for Quantum Materials of Zhejiang Province, Department of Physics, School of Science, Westlake University, Hangzhou, Zhejiang 310030, China
| | - Zhuang Qian
- Key Laboratory for Quantum Materials of Zhejiang Province, Department of Physics, School of Science, Westlake University, Hangzhou, Zhejiang 310030, China
| | - Shi Liu
- Key Laboratory for Quantum Materials of Zhejiang Province, Department of Physics, School of Science, Westlake University, Hangzhou, Zhejiang 310030, China
| |
Collapse
|
5
|
Song G, Wu Y, Cao L, Li G, Zhang B, Liang F, Gao B. Non-volatile control of topological phase transition in an asymmetric ferroelectric In 2Te 2S monolayer. Phys Chem Chem Phys 2023; 25:24696-24704. [PMID: 37668094 DOI: 10.1039/d3cp02616g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/06/2023]
Abstract
The coupling of topological electronic states and ferroelectricity is highly desired due to their abundant physical phenomenon and potential applications in multifunctional devices. However, it is difficult to achieve such a phenomenon in a single ferroelectric (FE) monolayer because the two polarized states are topologically equivalent. Here, we demonstrate that the symmetry of polarized states can be broken by constructing a Janus structure in a FE monolayer. We illustrate such a general idea by replacing a layer of Te atoms in the In2Te3 monolayer with S atoms. Using first-principles calculations, we show that the In2Te2S monolayer has two asymmetric polarized states, which are characterized by a metal and semiconductor, respectively. Importantly, as the spin-orbit coupling is included, a band gap (50.4 meV) is created in the metallic state, resulting in a non-trivial topological phase. Thus, it proves to be a feasible method to engineer non-volatile FE control of topological order in a single-phase system. We also demonstrate the underlying physical mechanism of topological phase transition, which is unveiled to be related to the weakened intrinsic electric field resulting from charge transfer. These interesting results provide a general way to design asymmetric FE materials and shed light on their potential application in non-volatile multifunctional devices.
Collapse
Affiliation(s)
- Guang Song
- Department of Physics, Huaiyin Institute of Technology, Huaian 223003, China.
| | - Yangyang Wu
- Department of Physics, Huaiyin Institute of Technology, Huaian 223003, China.
| | - Lei Cao
- Department of Physics, Huaiyin Institute of Technology, Huaian 223003, China.
| | - Guannan Li
- Department of Physics, Huaiyin Institute of Technology, Huaian 223003, China.
| | - Bingwen Zhang
- Fujian Key Laboratory of Functional Marine Sensing Materials, Minjiang University, Fuzhou 350108, China
| | - Feng Liang
- Department of Physics, Huaiyin Institute of Technology, Huaian 223003, China.
| | - Benling Gao
- Department of Physics, Huaiyin Institute of Technology, Huaian 223003, China.
| |
Collapse
|
6
|
Shekhar S, Oh Y, Jeong JY, Choi Y, Cho D, Hong S. Nanoscale mapping of edge-state conductivity and charge-trap activity in topological insulators. MATERIALS HORIZONS 2023; 10:2245-2253. [PMID: 37014136 DOI: 10.1039/d2mh01259f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We report the nanoscale mapping of topological edge-state conductivity and the effects of charge-traps on conductivity in a Bi2Se3 multilayer film under ambient conditions. In this strategy, we applied an electric field perpendicular to the surface plane of Bi2Se3via a conducting probe to directly map the charge-trap densities and conductivities with a nanoscale resolution. The results showed that edge regions had one-dimensional characteristics with higher conductivities (two orders) and lower charge-trap densities (four orders) than those of flat surface regions where their conductivities and charge-traps were dominated by bulk effects. Additionally, edges showed an enhanced conductivity with an elevated electric field, possibly due to the creation of new topological states by stronger spin-Hall effects. Importantly, we observed ultra-high photoconductivity predominantly on edge regions compared with that of flat surface regions, which was attributed to the excitation of edge-state carriers by light. Since our method provides an important insight into the charge transport in topological insulators, it could be a significant advancement in the development of error-tolerant topotronic devices.
Collapse
Affiliation(s)
- Shashank Shekhar
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul 08826, Korea.
| | - Yuhyeon Oh
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul 08826, Korea.
| | - Jin-Young Jeong
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul 08826, Korea.
| | - Yoonji Choi
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul 08826, Korea.
| | - Duckhyung Cho
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul 08826, Korea.
| | - Seunghun Hong
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul 08826, Korea.
| |
Collapse
|
7
|
Ke C, Hu Y, Liu S. Depolarization induced III-V triatomic layers with tristable polarization states. NANOSCALE HORIZONS 2023; 8:616-623. [PMID: 36945876 DOI: 10.1039/d3nh00026e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The integration of ferroelectrics that exhibit high dielectric, piezoelectric, and thermal compatibility with the mainstream semiconductor industry will enable novel device types for widespread applications, and yet there are few silicon-compatible ferroelectrics suitable for device downscaling. We demonstrate with first-principles calculations that the enhanced depolarization field at the nanoscale can be utilized to soften unswitchable wurtzite III-V semiconductors, resulting in ultrathin two-dimensional (2D) sheets possessing reversible polarization states. A 2D sheet of AlSb consisting of three atomic planes is identified to host both ferroelectricity and antiferroelectricity, and the tristate switching is accompanied by a metal-semiconductor transition. The thermodynamic stability and potential synthesizability of the triatomic layer are corroborated with phonon spectrum calculations, ab initio molecular dynamics simulations, and variable-composition evolutionary structure search. We propose a 2D AlSb-based homojunction field effect transistor that supports three distinct and nonvolatile resistance states. This new class of III-V semiconductor-derived 2D materials with dual ferroelectricity and antiferroelectricity opens up the opportunity for nonvolatile multibit-based integrated nanoelectronics.
Collapse
Affiliation(s)
- Changming Ke
- Key Laboratory for Quantum Materials of Zhejiang Province, Department of Physics, School of Science, Westlake University, Hangzhou, Zhejiang 310030, China.
- Institute of Natural Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Yihao Hu
- Key Laboratory for Quantum Materials of Zhejiang Province, Department of Physics, School of Science, Westlake University, Hangzhou, Zhejiang 310030, China.
- Institute of Natural Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Shi Liu
- Key Laboratory for Quantum Materials of Zhejiang Province, Department of Physics, School of Science, Westlake University, Hangzhou, Zhejiang 310030, China.
- Institute of Natural Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China
| |
Collapse
|
8
|
Sliding ferroelectricity in van der Waals layered γ-InSe semiconductor. Nat Commun 2023; 14:36. [PMID: 36596789 PMCID: PMC9810696 DOI: 10.1038/s41467-022-35490-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Accepted: 12/06/2022] [Indexed: 01/05/2023] Open
Abstract
Two-dimensional (2D) van-der-Waals (vdW) layered ferroelectric semiconductors are highly desired for in-memory computing and ferroelectric photovoltaics or detectors. Beneficial from the weak interlayer vdW-force, controlling the structure by interlayer twist/translation or doping is an effective strategy to manipulate the fundamental properties of 2D-vdW semiconductors, which has contributed to the newly-emerging sliding ferroelectricity. Here, we report unconventional room-temperature ferroelectricity, both out-of-plane and in-plane, in vdW-layered γ-InSe semiconductor triggered by yttrium-doping (InSe:Y). We determine an effective piezoelectric constant of ∼7.5 pm/V for InSe:Y flakes with thickness of ∼50 nm, about one order of magnitude larger than earlier reports. We directly visualize the enhanced sliding switchable polarization originating from the fantastic microstructure modifications including the stacking-faults elimination and a subtle rhombohedral distortion due to the intralayer compression and continuous interlayer pre-sliding. Our investigations provide new freedom degrees of structure manipulation for intrinsic properties in 2D-vdW-layered semiconductors to expand ferroelectric candidates for next-generation nanoelectronics.
Collapse
|
9
|
Liang Y, Zheng F, Zhao P, Wang Q, Frauenheim T. Intrinsic Ferroelectric Quantum Spin Hall Insulator in Monolayer Na 3Bi with Surface Trimerization. J Phys Chem Lett 2022; 13:11059-11064. [PMID: 36416532 DOI: 10.1021/acs.jpclett.2c03270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Two-dimensional (2D) ferroelectric quantum spin Hall (FEQSH) insulator, which features coexisting ferroelectric and topologically insulating orders in two-dimension, is generally considered available only in engineered 2D systems. This is detrimental to the synthesis and application of next generation nonvolatile functional candidates. Therefore, exploring the intrinsic 2D FEQSH insulator is crucial. Here, by means of first-principles, we report a long-thought intrinsic 2D FEQSH insulator in monolayer Na3Bi with surface trimerization. The material harbors merits including large ferroelectric polarization, sizable nontrivial band gap, and low switching barrier, which are particularly beneficial for the detection and observation of ferroelectric topologically insulating states. Also, it is capable of nonvolatile switching of nontrivial spin textures via inherent ferroelectricity. The fantastic combination of excellent ferroelectric and topological phases in intrinsic the Na3Bi monolayer serves as an alluring platform for accelerating both scientific discoveries and innovative applications.
Collapse
Affiliation(s)
- Yan Liang
- College of Physics and Optoelectronic Engineering, Faculty of Information Science and Engineering, Ocean University of China, Songling Road 238, Qingdao, 266100, People's Republic of China
| | - Fulu Zheng
- Bremen Center for Computational Materials Science, University of Bremen, Bremen, 28359, Germany
| | - Pei Zhao
- College of Physics and Optoelectronic Engineering, Faculty of Information Science and Engineering, Ocean University of China, Songling Road 238, Qingdao, 266100, People's Republic of China
| | - Qiang Wang
- Key laboratory for Microstructural Material Physics of Hebei Province, School of Science, Yanshan University, Qinhuangdao, 066104, People's Republic of China
| | - Thomas Frauenheim
- Bremen Center for Computational Materials Science, University of Bremen, Bremen, 28359, Germany
- Beijing Computational Science Research Center, Beijing, 100193, People's Republic of China
- Shenzhen JL Computational Science and Applied Research Institute, Shenzhen, 518109, People's Republic of China
| |
Collapse
|