1
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Zhang X, Wei H, Wu Y, Yang T, Cao B. Giant tunnel resistance effect in (SrTiO 3) 2/(BaTiO 3) 4/(CaTiO 3) 2 asymmetric superlattice with enhanced polarization. Phys Chem Chem Phys 2024; 26:2168-2174. [PMID: 38132888 DOI: 10.1039/d3cp04608g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
In this work, we report the effectively enhanced tunneling electroresistance effect in Au/(SrTiO3)2/(BaTiO3)4/(CaTiO3)2/Nb:SrTiO3 superlattice ferroelectric tunnel junction (FTJ). The stable polarization switching and enhanced ferroelectricity were achieved in the nanoscale thickness high-quality epitaxial superlattice. A high ON/OFF current ratio of more than 105 was obtained at room temperature, which is an order of magnitude larger than the BaTiO3 FTJ with the same structure. Nonvolatile resistance switching controlled by nonvolatile polarization switching was observed in the superlattice FTJ. Driven by increased polarization and intrinsic asymmetric ferroelectricity, a highly asymmetric depolarization field is generated compared with the Au/BaTiO3/Nb:SrTiO3 FTJ, resulting in an enhanced tunneling electroresistance effect. These results provide a potential way to construct FTJ memory devices by constructing asymmetric three-component ferroelectric superlattices.
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Affiliation(s)
- Xiubing Zhang
- School of Physics and Physical Engineering, Qufu Normal University, Qufu 273165, China.
| | - Haoming Wei
- School of Physics and Physical Engineering, Qufu Normal University, Qufu 273165, China.
| | - Yangqing Wu
- School of Physics and Physical Engineering, Qufu Normal University, Qufu 273165, China.
| | - Tengzhou Yang
- School of Physics and Physical Engineering, Qufu Normal University, Qufu 273165, China.
| | - Bingqiang Cao
- School of Material Science and Engineering, University of Jinan, Jinan 250022, Shandong, China.
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2
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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] [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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3
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Liu Z, Wang H, Li M, Tao L, Paudel TR, Yu H, Wang Y, Hong S, Zhang M, Ren Z, Xie Y, Tsymbal EY, Chen J, Zhang Z, Tian H. In-plane charged domain walls with memristive behaviour in a ferroelectric film. Nature 2023; 613:656-661. [PMID: 36653455 DOI: 10.1038/s41586-022-05503-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 11/01/2022] [Indexed: 01/19/2023]
Abstract
Domain-wall nanoelectronics is considered to be a new paradigm for non-volatile memory and logic technologies in which domain walls, rather than domains, serve as an active element. Especially interesting are charged domain walls in ferroelectric structures, which have subnanometre thicknesses and exhibit non-trivial electronic and transport properties that are useful for various nanoelectronics applications1-3. The ability to deterministically create and manipulate charged domain walls is essential to realize their functional properties in electronic devices. Here we report a strategy for the controllable creation and manipulation of in-plane charged domain walls in BiFeO3 ferroelectric films a few nanometres thick. By using an in situ biasing technique within a scanning transmission electron microscope, an unconventional layer-by-layer switching mechanism is detected in which ferroelectric domain growth occurs in the direction parallel to an applied electric field. Based on atomically resolved electron energy-loss spectroscopy, in situ charge mapping by in-line electron holography and theoretical calculations, we show that oxygen vacancies accumulating at the charged domain walls are responsible for the domain-wall stability and motion. Voltage control of the in-plane domain-wall position within a BiFeO3 film gives rise to multiple non-volatile resistance states, thus demonstrating the key functional property of being a memristor a few unit cells thick. These results promote a better understanding of ferroelectric switching behaviour and provide a new strategy for creating unit-cell-scale devices.
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Affiliation(s)
- Zhongran Liu
- Center of Electron Microscopy, School of Materials Science and Engineering, Zhejiang University, Hangzhou, China
| | - Han Wang
- Department of Materials Science and Engineering, National University of Singapore, Singapore City, Singapore.,Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, China
| | - Ming Li
- Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, NE, USA
| | - Lingling Tao
- Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, NE, USA
| | - Tula R Paudel
- Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, NE, USA.,Department of Physics, South Dakota School of Mines and Technology, Rapid City, SD, USA
| | - Hongyang Yu
- Center of Electron Microscopy, School of Materials Science and Engineering, Zhejiang University, Hangzhou, China
| | - Yuxuan Wang
- Center of Electron Microscopy, School of Materials Science and Engineering, Zhejiang University, Hangzhou, China
| | - Siyuan Hong
- Department of Physics, Zhejiang University, Hangzhou, China
| | - Meng Zhang
- Department of Physics, Zhejiang University, Hangzhou, China
| | - Zhaohui Ren
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou, China
| | - Yanwu Xie
- Department of Physics, Zhejiang University, Hangzhou, China
| | - Evgeny Y Tsymbal
- Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, NE, USA.
| | - Jingsheng Chen
- Department of Materials Science and Engineering, National University of Singapore, Singapore City, Singapore.
| | - Ze Zhang
- Center of Electron Microscopy, School of Materials Science and Engineering, Zhejiang University, Hangzhou, China. .,State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou, China.
| | - He Tian
- Center of Electron Microscopy, School of Materials Science and Engineering, Zhejiang University, Hangzhou, China. .,State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou, China. .,School of Physics and Microelectronics, Zhengzhou University, Zhengzhou, China.
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Zhang Q, Li X, Zhu J. Direct Observation of Interface-Dependent Multidomain State in the BaTiO 3 Tunnel Barrier of a Multiferroic Tunnel Junction Memristor. ACS APPLIED MATERIALS & INTERFACES 2021; 13:43641-43647. [PMID: 34473930 DOI: 10.1021/acsami.1c11661] [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
Multiferroic tunnel junctions (MFTJs), normally consisting of a four-state resistance, have been studied extensively as a potential candidate for nonvolatile memory devices. More interestingly, the MFTJs whose resistance can be tuned continuously with applied voltage were also reported recently. Since the performance of MFTJs is closely related to their interfacial structures, it is necessary to investigate MFTJs at the atomic scale. In this work, atomic-resolution HAADF, ABF, and EELS of the La0.7Sr0.3MnO3/BaTiO3/La0.7Sr0.3MnO3 MFTJ memristor have been obtained with aberration-corrected scanning transmission electron microscopy (STEM). These results demonstrate varied degree of interfacial cation intermixing at the bottom BTO/LSMO interface, which has a direct influence on the polarization of the ferroelectric barrier BTO and the electronic structure of Mn near the interfaces. We also took advantage of a simplified model to explain the relation between the interfacial behavior and polarization states, which could be a contributing factor to the transport properties of this MFTJ.
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Affiliation(s)
- Qiqi Zhang
- National Center for Electron Microscopy in Beijing, School of Materials Science and Engineering, The State Key Laboratory of New Ceramics and Fine Processing, Key Laboratory of Advanced Materials (MOE), Tsinghua University, Beijing 100084, People's Republic of China
- Ji Hua Laboratory, Foshan 528000, People's Republic of China
| | - Xiaoguang Li
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Physics, and CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics, University of Science and Technology of China, Hefei 230000, People's Republic of China
| | - Jing Zhu
- National Center for Electron Microscopy in Beijing, School of Materials Science and Engineering, The State Key Laboratory of New Ceramics and Fine Processing, Key Laboratory of Advanced Materials (MOE), Tsinghua University, Beijing 100084, People's Republic of China
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Xiao W, Kang L, Hao H, Zhou Y, Zhang L, Zheng X, Zeng Z. Giant tunneling electroresistance arising from reversible partial barrier metallization in the NaTiO 3/BaTiO 3/LaTiO 3 ferroelectric tunnel junction. Phys Chem Chem Phys 2021; 23:16349-16356. [PMID: 34318829 DOI: 10.1039/d1cp01767e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Tunneling electroresistance (TER) is the change in tunneling resistance induced by ferroelectric polarization reversal in ferroelectric tunnel junctions (FTJs), and how to achieve a giant TER has always been a central topic in the study of FTJs. In this work, by considering the NaTiO3/BaTiO3/LaTiO3 junction with asymmetric polar interfaces as an example, we propose a novel scheme to realize a giant TER based on the reversible partial metallization of ferroelectric barrier upon the switching of ferroelectric polarization. Density functional theory calculations indicate that high on-state and low off-state conductances are obtained and the TER ratio is as high as 3.20 × 108% due to the reversible partial barrier metallization, which leads to a great difference in the effective tunneling barrier widths. The reversible partial barrier metallization, accompanied by the ferroelectric polarization reversal, is driven by the parallel or anti-parallel alignment of the depolarization electrical field of the ferroelectrical barrier and a strong built-in electrical field cooperatively contributed by the asymmetric polar interfaces and the difference in the work functions of the two leads. The findings suggest a feasible scheme for constructing promising high performance FTJ memory devices by combining both asymmetric polar interfaces and substantially different work functions.
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Affiliation(s)
- Wei Xiao
- Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China.
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Ding J, Shao DF, Li M, Wen LW, Tsymbal EY. Two-Dimensional Antiferroelectric Tunnel Junction. PHYSICAL REVIEW LETTERS 2021; 126:057601. [PMID: 33605764 DOI: 10.1103/physrevlett.126.057601] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 05/17/2020] [Accepted: 01/08/2021] [Indexed: 06/12/2023]
Abstract
Ferroelectric tunnel junctions (FTJs), which consist of two metal electrodes separated by a thin ferroelectric barrier, have recently aroused significant interest for technological applications as nanoscale resistive switching devices. So far, most existing FTJs have been based on perovskite-oxide barrier layers. The recent discovery of the two-dimensional (2D) van der Waals ferroelectric materials opens a new route to realize tunnel junctions with new functionalities and nm-scale dimensions. Because of the weak coupling between the atomic layers in these materials, the relative dipole alignment between them can be controlled by applied voltage. This allows transitions between ferroelectric and antiferroelectric orderings, resulting in significant changes of the electronic structure. Here, we propose to realize 2D antiferroelectric tunnel junctions (AFTJs), which exploit this new functionality, based on bilayer In_{2}X_{3} (X=S, Se, Te) barriers and different 2D electrodes. Using first-principles density functional theory calculations, we demonstrate that the In_{2}X_{3} bilayers exhibit stable ferroelectric and antiferroelectric states separated by sizable energy barriers, thus supporting a nonvolatile switching between these states. Using quantum-mechanical modeling of the electronic transport, we explore in-plane and out-of-plane tunneling across the In_{2}S_{3} van der Waals bilayers, and predict giant tunneling electroresistance effects and multiple nonvolatile resistance states driven by ferroelectric-antiferroelectric order transitions. Our proposal opens a new route to realize nanoscale memory devices with ultrahigh storage density using 2D AFTJs.
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Affiliation(s)
- Jun Ding
- Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, Nebraska 68588-0299, USA
- College of Science, Henan University of Engineering, Zhengzhou 451191, People's Republic of China
| | - Ding-Fu Shao
- Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, Nebraska 68588-0299, USA
| | - Ming Li
- Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, Nebraska 68588-0299, USA
| | - Li-Wei Wen
- College of Science, Henan University of Engineering, Zhengzhou 451191, People's Republic of China
| | - Evgeny Y Tsymbal
- Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, Nebraska 68588-0299, USA
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