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Dai M, Tang Z, Luo X, Zheng Y. Realizing multiple non-volatile resistance states in a two-dimensional domain wall ferroelectric tunneling junction. Nanoscale 2023; 15:9171-9178. [PMID: 37144440 DOI: 10.1039/d3nr00522d] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Two-dimensional ferroelectric tunnel junctions (2D FTJs) with an ultrathin van der Waals ferroelectrics sandwiched by two electrodes have great applications in memory and synaptic devices. Domain walls (DWs), formed naturally in ferroelectrics, are being actively explored for their low energy consumption, reconfigurable, and non-volatile multi-resistance characteristics in memory, logic and neuromorphic devices. However, DWs with multiple resistance states in 2D FTJ have rarely been explored and reported. Here, we propose the formation of 2D FTJ with multiple non-volatile resistance states manipulated by neutral DWs in a nanostripe-ordered β'-In2Se3 monolayer. By combining density functional theory (DFT) calculations with nonequilibrium Green's function method, we found that a large TER ratio can be obtained due to the blocking effect of DWs on the electronic transmission. Multiple conductance states are readily obtained by introducing different numbers of the DWs. This work opens a new route to designing multiple non-volatile resistance states in 2D DW-FTJ.
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Affiliation(s)
- Minzhi Dai
- Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices, School of Physics, Sun Yat-sen University, Guangzhou 510275, China.
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, 510275, Guangzhou, China
- Centre for Physical Mechanics and Biophysics, School of Physics, Sun Yat-sen University, 510275, Guangzhou, China
| | - Zhiyuan Tang
- Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices, School of Physics, Sun Yat-sen University, Guangzhou 510275, China.
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, 510275, Guangzhou, China
- Centre for Physical Mechanics and Biophysics, School of Physics, Sun Yat-sen University, 510275, Guangzhou, China
| | - Xin Luo
- Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices, School of Physics, Sun Yat-sen University, Guangzhou 510275, China.
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, 510275, Guangzhou, China
- Centre for Physical Mechanics and Biophysics, School of Physics, Sun Yat-sen University, 510275, Guangzhou, China
| | - Yue Zheng
- Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices, School of Physics, Sun Yat-sen University, Guangzhou 510275, China.
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, 510275, Guangzhou, China
- Centre for Physical Mechanics and Biophysics, School of Physics, Sun Yat-sen University, 510275, Guangzhou, China
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Chi X, Guo R, Xiong J, Ren L, Peng X, Tay BK, Chen J. Enhanced Tunneling Magnetoresistance Effect via Ferroelectric Control of Interface Electronic/Magnetic Reconstructions. ACS Appl Mater Interfaces 2021; 13:56638-56644. [PMID: 34786928 DOI: 10.1021/acsami.1c15836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Magnetic tunnel junctions (MTJs) with tunable tunneling magnetoresistances (TMR) have already been proven to have great potential for spintronics. Especially, when ferroelectric materials are used as insulating barriers, more novel functions of MTJs can be realized due to interface magnetoelectric coupling. Here, we demonstrate a very large ferroelectric modulation of TMR (as high as 570% in low-resistance state) in the ferroelectric/magnetic La0.5Sr0.5MnO3/BaTiO3 (LSMO/BTO) junctions and find robust interfacial electronic and magnetic reconstructions via ferroelectric polarization switching. Through electrical, magnetic, and optical measurements combined with X-ray absorption and magnetic circular dichroism, we reveal that the interfacial electronic and magnetic (ferromagnetic/antiferromagnetic phase transition) reconstructions originate from strong electromagnetic coupling between BTO and LSMO at the interface and are driven by the modulation of hole/electron doping at the interface of LSMO/BTO through ferroelectric polarization switching. As a result, the ferroelectrically controlled interface barrier height and width and spin filter effect enable a giant electrical modulation of TMR. Our results shed new light on the intrinsic mechanisms governing magnetoelectric coupling and offering a new route to enhance magnetoelectric coupling for spin control in spintronic devices.
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Affiliation(s)
- Xiao Chi
- State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510641, China
| | - Rui Guo
- Department of Materials Science and Engineering, National University of Singapore, 117575, Singapore
- Centre for Micro- and Nano-Electronics (CMNE), School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore
- UMI 3288 CINTRA (CNRS-NTU-THALES Research Alliances), Nanyang Technological University, Research Techno Plaza, 50 Nanyang Drive, 637553 Singapore
| | - Juxia Xiong
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, P.R. China
| | - Lizhu Ren
- Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, 117583 Singapore
| | - Xinwen Peng
- State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510641, China
| | - Beng Kang Tay
- Centre for Micro- and Nano-Electronics (CMNE), School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore
- UMI 3288 CINTRA (CNRS-NTU-THALES Research Alliances), Nanyang Technological University, Research Techno Plaza, 50 Nanyang Drive, 637553 Singapore
| | - Jingsheng Chen
- Department of Materials Science and Engineering, National University of Singapore, 117575, Singapore
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Peng Q, Li D, Huang P, Ren Y, Li Z, Pi L, Chen P, Wu M, Zhang X, Zhou X, Zhai T. Room-Temperature Ferroelectricity in 2D Metal-Tellurium-Oxyhalide Cd 7Te 7Cl 8O 17 via Selenium-Induced Selective-Bonding Growth. ACS Nano 2021; 15:16525-16532. [PMID: 34559511 DOI: 10.1021/acsnano.1c06099] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Two-dimensional (2D) ferroelectric materials have attracted increasing interest due to meeting the requirements of integration, miniaturization, and multifunction of devices. However, the exploration of intrinsic 2D ferroelectric materials is still in the early stage, for which the related reports are still limited, especially fewer ones prepared by chemical vapor deposition (CVD). Here, the ultrathin metal-tellurium-oxyhalide Cd7Te7Cl8O17 (CTCO) flakes as thin as 3.8 nm are realized via the selenium-induced selective-bonding CVD method. The growth mechanism has been confirmed by experiments and theoretical calculations, which can be ascribed to the induction of selective bonding of a hydrogen atom in H2O molecules by the introduction of selenium, leading to the generation of strong oxidants. Excitingly, switchable out-of-plane ferroelectric polarization was observed in CTCO flakes down to 6 nm at room temperature, which may be caused by mobile Cl vacancies. This work has implications for the synthesis and applications of 2D ferroelectric materials.
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Affiliation(s)
- Qiaojun Peng
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Sciences and Engineering, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
| | - Dongyan Li
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Sciences and Engineering, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
| | - Pu Huang
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, People's Republic of China
| | - Yangyang Ren
- School of Physics, Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
| | - Zexin Li
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Sciences and Engineering, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
| | - Lejing Pi
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Sciences and Engineering, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
| | - Ping Chen
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Sciences and Engineering, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
| | - Menghao Wu
- School of Physics, Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
| | - Xiuwen Zhang
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, People's Republic of China
| | - Xing Zhou
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Sciences and Engineering, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
| | - Tianyou Zhai
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Sciences and Engineering, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
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Abstract
Ferroelectric tunnel junctions (FTJs) utilizing an in-plane head-to-head ferroelectric domain wall (DW) have recently been realized, showing interesting physics and new functionalities. However, the DW state in these junctions was found to be metastable and not reversible after applying an electric field. In this work, we demonstrate that a stable and reversible head-to-head DW state can be achieved in FTJs by proper engineering of polar interfaces. Using density functional theory (DFT) calculations and phenomenological modeling, we explore the DW stability by varying stoichiometry of the La_{1-x}Sr_{x}O/TiO_{2} interfaces in FTJs with La_{0.5}Sr_{0.5}MnO_{3} electrodes and a ferroelectric BaTiO_{3} tunnel barrier. For, x≤0.4 we find that the DW state becomes a global minimum and the calculated hysteresis loops exhibit three reversible polarization states. For such FTJs, our quantum transport calculations predict the emergence of a DW tunneling electroresistance effect-reversible switching of the tunneling conductance between the highly conductive DW state and two much less conductive uniform polarization states.
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Affiliation(s)
- M Li
- Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, Nebraska 68588, USA
| | - L L Tao
- Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, Nebraska 68588, USA
| | - Evgeny Y Tsymbal
- Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, Nebraska 68588, USA
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Yang Q, Tao L, Zhang Y, Li M, Jiang Z, Tsymbal EY, Alexandrov V. Ferroelectric Tunnel Junctions Enhanced by a Polar Oxide Barrier Layer. Nano Lett 2019; 19:7385-7393. [PMID: 31514498 DOI: 10.1021/acs.nanolett.9b03056] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Ferroelectric tunnel junctions (FTJs) have recently aroused significant interest due to the interesting physics controlling their properties and potential application in nonvolatile memory devices. In this work, we propose a new concept to design high-performance FTJs based on ferroelectric/polar-oxide composite barriers. Using density functional theory calculations, we model electronic and transport properties of LaNiO3/PbTiO3/LaAlO3/LaNiO3 tunnel junctions and demonstrate that an ultrathin polar LaAlO3(001) layer strongly enhances their performance. We predict a tunneling electroresistance (TER) effect in these FTJs with an OFF/ON resistance ratio exceeding a factor of 104 and ON state resistance as low as about 1 kΩμm2. Such an enhanced performance is driven by the ionic charge at the PbTiO3/LaAlO3 interface, which significantly increases transmission across the FTJ when the ferroelectric polarization of PbTiO3 is pointing against the intrinsic electric field produced by this ionic charge. This is due to the formation of a two-dimensional (2D) electron or hole gas, depending on the LaAlO3 termination being (LaO)+ or (AlO2)-, respectively, which is formed to screen the polarization charge of the nonuniform polarization state. This 2D electron (hole) gas can be switched ON and OFF by the reversal of ferroelectric polarization, resulting in the giant TER effect. The proposed design suggests a new direction for creating FTJs with a stable and reversible ferroelectric polarization, a sizable TER effect, and a low-resistance-area product, as required for memory applications.
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Affiliation(s)
- Qiong Yang
- Department of Chemical and Biomolecular Engineering , University of Nebraska , Lincoln , Nebraska 68588 , United States
- School of Materials Science and Engineering , Xiangtan University , Xiangtan , Hunan 411105 , China
| | - Lingling Tao
- Department of Physics and Astronomy , University of Nebraska , Lincoln , Nebraska 68588 , United States
| | - Yuke Zhang
- School of Materials Science and Engineering , Xiangtan University , Xiangtan , Hunan 411105 , China
| | - Ming Li
- Department of Physics and Astronomy , University of Nebraska , Lincoln , Nebraska 68588 , United States
| | - Zhen Jiang
- Department of Chemical and Biomolecular Engineering , University of Nebraska , Lincoln , Nebraska 68588 , United States
| | - Evgeny Y Tsymbal
- Department of Physics and Astronomy , University of Nebraska , Lincoln , Nebraska 68588 , United States
| | - Vitaly Alexandrov
- Department of Chemical and Biomolecular Engineering , University of Nebraska , Lincoln , Nebraska 68588 , United States
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Yuan S, Luo X, Chan HL, Xiao C, Dai Y, Xie M, Hao J. Room-temperature ferroelectricity in MoTe 2 down to the atomic monolayer limit. Nat Commun 2019; 10:1775. [PMID: 30992431 PMCID: PMC6467908 DOI: 10.1038/s41467-019-09669-x] [Citation(s) in RCA: 128] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 03/17/2019] [Indexed: 12/02/2022] Open
Abstract
Ferroelectrics allow for a wide range of intriguing applications. However, maintaining ferroelectricity has been hampered by intrinsic depolarization effects. Here, by combining first-principles calculations and experimental studies, we report on the discovery of robust room-temperature out-of-plane ferroelectricity which is realized in the thinnest monolayer MoTe2 with unexploited distorted 1T (d1T) phase. The origin of the ferroelectricity in d1T-MoTe2 results from the spontaneous symmetry breaking due to the relative atomic displacements of Mo atoms and Te atoms. Furthermore, a large ON/OFF resistance ratio is achieved in ferroelectric devices composed of MoTe2-based van der Waals heterostructure. Our work demonstrates that ferroelectricity can exist in two-dimensional layered material down to the atomic monolayer limit, which can result in new functionalities and achieve unexpected applications in atomic-scale electronic devices. It is difficult to maintain ferroelectricity in the two dimensional limit. Here, the authors report robust room-temperature ferroelectricity in the thinnest monolayer MoTe2 due to relative atomic displacements of Mo and Te atoms.
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Affiliation(s)
- Shuoguo Yuan
- Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong, PR China
| | - Xin Luo
- Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong, PR China.,School of Physics, Sun Yat-sen University, Guangzhou, 510275, PR China
| | - Hung Lit Chan
- Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong, PR China
| | - Chengcheng Xiao
- Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong, PR China
| | - Yawei Dai
- Department of Physics, The University of Hong Kong, Pokfulam Road, Hong Kong, PR China
| | - Maohai Xie
- Department of Physics, The University of Hong Kong, Pokfulam Road, Hong Kong, PR China
| | - Jianhua Hao
- Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong, PR China.
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