1
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Yin H, Zhu H, Wang S, Jin K. Novel 2DEG System at the HfO 2/STO Interface. ACS APPLIED MATERIALS & INTERFACES 2024; 16:26915-26921. [PMID: 38717847 DOI: 10.1021/acsami.4c03115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2024]
Abstract
Multifunctional integration in a single device has always been a hot research topic, especially for contradictory phenomena, one of which is the coexistence of ferroelectricity and metallicity. The complex oxide heterostructures, as symmetric breaking systems, provide a great possibility to incorporate different properties. Moreover, finding a series of oxide heterostructures to achieve this goal remains as a challenge. Here, taking the advantage of different physical phenomena, we use H2 plasma to pretreat the SrTiO3 (STO) substrate and then fabricate HfO2/STO heterostructures with it. The novel, well-repeatable metallic two-dimensional electron gas (2DEG) is directly obtained at the heterointerfaces without any further complex procedures, while the obvious ferroelectric-like behavior and Rashba spin-orbit coupling are also observed. The understanding of the mechanism, as well as the modified facile preparation procedure, would be meaningful for further development of ferroelectric metal in complex oxide heterostructures.
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Affiliation(s)
- Hang Yin
- Shaanxi Key Laboratory of Condensed Matter Structures and Properties and MOE Key Laboratory of Materials Physics and Chemistry Under Extraordinary Conditions, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an 710072, China
| | - Huapei Zhu
- Shaanxi Key Laboratory of Condensed Matter Structures and Properties and MOE Key Laboratory of Materials Physics and Chemistry Under Extraordinary Conditions, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an 710072, China
| | - Shuanhu Wang
- Shaanxi Key Laboratory of Condensed Matter Structures and Properties and MOE Key Laboratory of Materials Physics and Chemistry Under Extraordinary Conditions, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an 710072, China
| | - Kexin Jin
- Shaanxi Key Laboratory of Condensed Matter Structures and Properties and MOE Key Laboratory of Materials Physics and Chemistry Under Extraordinary Conditions, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an 710072, China
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2
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Gao H, Tang Y, Liao Q, Zhao X, Wang B. First-Principles Study on Evolution of Magnetic Domain in Two-Dimensional BaTiO 3 Ultrathin Film Doped with Co under Electric Field. NANOMATERIALS (BASEL, SWITZERLAND) 2024; 14:586. [PMID: 38607121 PMCID: PMC11013782 DOI: 10.3390/nano14070586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 03/19/2024] [Accepted: 03/20/2024] [Indexed: 04/13/2024]
Abstract
The magnetization mechanism of Co-doped BaTiO3 ultrathin films is a subject of debate, which results in difficulties with the design of new multiferroics based on BaTiO3 matrixes. With the aid of a first-principles approach, it was observed that when the interstitial site and Ti vacancy were filled with Co, the configuration behaved in a nonmagnetic manner, indicating the significance of the Co content. Moreover, in the case of Co substituting two neighboring Ti atoms, when a direct current field was applied in the [100] direction, the magnetic domains excluding those in the [100], [010], and [001] directions were directed away. Further, the magnetoelectric constant was evaluated at ~449.3 mV/cmOe, showing strong magnetoelectric coupling at room temperature. Clearly, our study indicates that strict control of Ba, Ti, O, and Co stoichiometry can induce an electric and magnetic field conversion in two-dimensional BaTiO3 and may provide a new candidate for single-phase multiferroics for application in next-generation multifunctional devices.
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Affiliation(s)
| | | | | | - Xiangyu Zhao
- School of Electrical and Information Engineering, Panzhihua University, Panzhihua 617000, China; (H.G.); (Y.T.); (Q.L.)
| | - Bing Wang
- School of Electrical and Information Engineering, Panzhihua University, Panzhihua 617000, China; (H.G.); (Y.T.); (Q.L.)
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3
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Jiang Y, Parsonnet E, Qualls A, Zhao W, Susarla S, Pesquera D, Dasgupta A, Acharya M, Zhang H, Gosavi T, Lin CC, Nikonov DE, Li H, Young IA, Ramesh R, Martin LW. Enabling ultra-low-voltage switching in BaTiO 3. NATURE MATERIALS 2022; 21:779-785. [PMID: 35618823 DOI: 10.1038/s41563-022-01266-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 04/20/2022] [Indexed: 06/15/2023]
Abstract
Single crystals of BaTiO3 exhibit small switching fields and energies, but thin-film performance is considerably worse, thus precluding their use in next-generation devices. Here, we demonstrate high-quality BaTiO3 thin films with nearly bulk-like properties. Thickness scaling provides access to the coercive voltages (<100 mV) and fields (<10 kV cm-1) required for future applications and results in a switching energy of <2 J cm-3 (corresponding to <2 aJ per bit in a 10 × 10 × 10 nm3 device). While reduction in film thickness reduces coercive voltage, it does so at the expense of remanent polarization. Depolarization fields impact polar state stability in thicker films but fortunately suppress the coercive field, thus driving a deviation from Janovec-Kay-Dunn scaling and enabling a constant coercive field for films <150 nm in thickness. Switching studies reveal fast speeds (switching times of ~2 ns for 25-nm-thick films with 5-µm-diameter capacitors) and a pathway to subnanosecond switching. Finally, integration of BaTiO3 thin films onto silicon substrates is shown. We also discuss what remains to be demonstrated to enable the use of these materials for next-generation devices.
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Affiliation(s)
- Y Jiang
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - E Parsonnet
- Department of Physics, University of California, Berkeley, CA, USA
| | - A Qualls
- Department of Physics, University of California, Berkeley, CA, USA
| | - W Zhao
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | - S Susarla
- National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - D Pesquera
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
- Catalan Institute of Nanoscience and Nanotechnology, CSIC and BIST, Barcelona, Spain
| | - A Dasgupta
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | - M Acharya
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - H Zhang
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | - T Gosavi
- Components Research, Intel Corporation, Hillsboro, OR, USA
| | - C-C Lin
- Components Research, Intel Corporation, Hillsboro, OR, USA
| | - D E Nikonov
- Components Research, Intel Corporation, Hillsboro, OR, USA
| | - H Li
- Components Research, Intel Corporation, Hillsboro, OR, USA
| | - I A Young
- Components Research, Intel Corporation, Hillsboro, OR, USA
| | - R Ramesh
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Physics, University of California, Berkeley, CA, USA
| | - L W Martin
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA.
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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4
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Banerjee W, Kashir A, Kamba S. Hafnium Oxide (HfO 2 ) - A Multifunctional Oxide: A Review on the Prospect and Challenges of Hafnium Oxide in Resistive Switching and Ferroelectric Memories. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2107575. [PMID: 35510954 DOI: 10.1002/smll.202107575] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Revised: 03/24/2022] [Indexed: 06/14/2023]
Abstract
Hafnium oxide (HfO2 ) is one of the mature high-k dielectrics that has been standing strong in the memory arena over the last two decades. Its dielectric properties have been researched rigorously for the development of flash memory devices. In this review, the application of HfO2 in two main emerging nonvolatile memory technologies is surveyed, namely resistive random access memory and ferroelectric memory. How the properties of HfO2 equip the former to achieve superlative performance with high-speed reliable switching, excellent endurance, and retention is discussed. The parameters to control HfO2 domains are further discussed, which can unleash the ferroelectric properties in memory applications. Finally, the prospect of HfO2 materials in emerging applications, such as high-density memory and neuromorphic devices are examined, and the various challenges of HfO2 -based resistive random access memory and ferroelectric memory devices are addressed with a future outlook.
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Affiliation(s)
- Writam Banerjee
- Center for Single Atom-based Semiconductor Device, Department of Material Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Alireza Kashir
- Institute of Physics of the Czech Academy of Sciences, Na Slovance 2, Prague 8, 182 21, Czech Republic
| | - Stanislav Kamba
- Institute of Physics of the Czech Academy of Sciences, Na Slovance 2, Prague 8, 182 21, Czech Republic
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5
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Kwak Y, Han W, Lee JS, Song J, Kim J. Hysteretic temperature dependence of resistance controlled by gate voltage in LaAlO 3/SrTiO 3 heterointerface electron system. Sci Rep 2022; 12:6458. [PMID: 35440752 PMCID: PMC9019089 DOI: 10.1038/s41598-022-10425-3] [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: 11/04/2021] [Accepted: 04/07/2022] [Indexed: 11/29/2022] Open
Abstract
For two-dimensional electron gas device applications, it is important to understand how electrical-transport properties are controlled by gate voltage. Here, we report gate voltage-controllable hysteresis in the resistance–temperature characteristics of two-dimensional electron gas at LaAlO3/SrTiO3 heterointerface. Electron channels made of the LaAlO3/SrTiO3 heterointerface showed hysteretic resistance–temperature behavior: the measured resistance was significantly higher during upward temperature sweeps in thermal cycling tests. Such hysteretic behavior was observed only after application of positive back-gate voltages below 50 K in the thermal cycle, and the magnitude of hysteresis increased with the applied back-gate voltage. To explain this gate-controlled resistance hysteresis, we propose a mechanism based on electron trapping at impurity sites, in conjunction with the strong temperature-dependent dielectric constant of the SrTiO3 substrate. Our model explains well the observed gate-controlled hysteresis of the resistance–temperature characteristics, and the mechanism should be also applicable to other SrTiO3-based oxide systems, paving the way to applications of oxide heterostructures to electronic devices.
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Affiliation(s)
- Yongsu Kwak
- Korea Research Institute of Standards and Science, Daejeon, 34113, South Korea.,Department of Physics, Chungnam National University, Daejeon, 34134, South Korea
| | - Woojoo Han
- Korea Research Institute of Standards and Science, Daejeon, 34113, South Korea.,Department of Nanoscience, University of Science and Technology, Daejeon, 34113, South Korea
| | - Joon Sung Lee
- Display and Semiconductor Physics, Korea University Sejong Campus, Sejong, 30019, South Korea
| | - Jonghyun Song
- Department of Physics, Chungnam National University, Daejeon, 34134, South Korea. .,Institute of Quantum Systems (IQS), Chungnam National University, Daejeon, 34134, South Korea.
| | - Jinhee Kim
- Korea Research Institute of Standards and Science, Daejeon, 34113, South Korea.
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6
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Qi L, Ruan S, Zeng YJ. Review on Recent Developments in 2D Ferroelectrics: Theories and Applications. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2005098. [PMID: 33577141 DOI: 10.1002/adma.202005098] [Citation(s) in RCA: 66] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 09/28/2020] [Indexed: 06/12/2023]
Abstract
Although only a few 2D materials have been predicted to possess ferroelectricity, 2D ferroelectrics are expected to play a dominant role in the upcoming nano era as important functional materials. The ferroelectric properties of 2D ferroelectrics are significantly different than those of traditional bulk ferroelectrics owing to their intrinsic size and surface effects. To date, 2D ferroelectrics have been reported to exhibit diverse properties ranging from bulk photovoltaic and piezoelectric/pyroelectric effects to the spontaneous valley and spin polarization. These properties are either dependent on ferroelectric polarization or coupled with it for easy electric control, thus making 2D ferroelectrics applicable to multifunctional nanodevices. At present, cumulative efforts are being made to explore 2D ferroelectrics in theories, experiments, and applications. Herein, such theories and methods are briefly introduced. Subsequently, intrinsic and extrinsic origins of 2D ferroelectricity are separately summarized. In addition, invented or laboratory-validated 2D ferroelectric-based applications are listed. Finally, the existing challenges and prospects of 2D ferroelectrics are discussed.
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Affiliation(s)
- Lu Qi
- Key laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, P. R. China
| | - Shuangchen Ruan
- College of New Materials and New Energies, Shenzhen Technology University, Shenzhen, 518118, P. R. China
| | - Yu-Jia Zeng
- Key laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, P. R. China
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7
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Gao W, Chelikowsky JR. Prediction of Intrinsic Ferroelectricity and Large Piezoelectricity in Monolayer Arsenic Chalcogenides. NANO LETTERS 2020; 20:8346-8352. [PMID: 33135906 DOI: 10.1021/acs.nanolett.0c03511] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Two-dimensional materials that exhibit spontaneous electric polarization are of notable interest for functional materials. However, despite the prediction of many two-dimensional polar materials, the number of experimentally confirmed two-dimensional ferroelectrics is far less than bulk ferroelectrics. We provide strong evidence that the Pmn21 phase of arsenic chalcogenides As2X3 (X = S, Se, and Te), which include the recently isolated monolayer orpiment, are intrinsic ferroelectrics and demonstrate strong in-plane piezoelectricity. We found the calculated energy barriers for collectively reversing the electric polarization or moving a 180° domain wall are reasonable compared to previously reported ferroelectrics. We propose a high-symmetry structure (with Pmmn space group) that transforms into the ferroelectric Pmn21 phase by a soft B2u phonon mode. By studying other soft modes of the high-symmetry Pmmn structure, we identify several undiscovered metastable polymorphs, including a polar phase (with a P21 space group) with sizable piezoelectricity.
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Affiliation(s)
- Weiwei Gao
- Center for Computational Materials, Oden Institute for Computational Engineering and Sciences, The University of Texas at Austin, Austin, Texas 78712, United States
| | - James R Chelikowsky
- Center for Computational Materials, Oden Institute for Computational Engineering and Sciences, The University of Texas at Austin, Austin, Texas 78712, United States
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712, United States
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712, United States
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8
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He R, Lin JL, Liu Q, Liao Z, Shui L, Wang ZJ, Zhong Z, Li RW. Emergent Ferroelectricity in Otherwise Nonferroelectric Oxides by Oxygen Vacancy Design at Heterointerfaces. ACS APPLIED MATERIALS & INTERFACES 2020; 12:45602-45610. [PMID: 32929952 DOI: 10.1021/acsami.0c13314] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Introducing point defects in complex metal oxides is a very effective route to engineer crystal symmetry and therefore control physical properties. However, the inversion symmetry breaking, which is vital for many tantalizing properties, such as ferroelectricity and chiral spin structure, is usually hard to be induced in the bulk crystal by point defects. By designing the oxygen vacancy formation energy profile and migration path across the oxide heterostructure, our first-principles density functional theory (DFT) calculations demonstrate that the point defects can effectively break the inversion symmetry and hence create novel ferroelectricity in superlattices consisting of otherwise nonferroelectric materials SrTiO3 and SrRuO3. This induced ferroelectricity can be significantly enhanced by reducing the SrTiO3 thickness. Inspired by theory calculation, SrTiO3/SrRuO3 superlattices were experimentally fabricated and are found to exhibit surprising strong ferroelectric properties. Our finding paves a simple and effective pathway to engineer the inversion symmetry and thus properties by point defect control in oxide heterostructures.
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Affiliation(s)
- Ri He
- Key Laboratory of Magnetic Materials Devices & Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
- School of Information and Optoelectronic Science and Engineering, South China Normal University, Guangzhou 510006, China
- International Academy of Optoelectronics at Zhaoqing, South China Normal University, Zhaoqing 526238, China
| | - Jun Liang Lin
- College of Light Industry, Liaoning University, Shenyang 110036, China
- School of Materials Science and Engineering, Northeastern University, Shenyang 110819, China
| | - Qing Liu
- Key Laboratory of Magnetic Materials Devices & Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Zhaoliang Liao
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230026, China
| | - Lingling Shui
- School of Information and Optoelectronic Science and Engineering, South China Normal University, Guangzhou 510006, China
| | - Zhan Jie Wang
- School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110870, China
| | - Zhicheng Zhong
- Key Laboratory of Magnetic Materials Devices & Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
- China Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Run-Wei Li
- Key Laboratory of Magnetic Materials Devices & Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
- China Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
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9
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Higashitarumizu N, Kawamoto H, Lee CJ, Lin BH, Chu FH, Yonemori I, Nishimura T, Wakabayashi K, Chang WH, Nagashio K. Purely in-plane ferroelectricity in monolayer SnS at room temperature. Nat Commun 2020; 11:2428. [PMID: 32415121 PMCID: PMC7229038 DOI: 10.1038/s41467-020-16291-9] [Citation(s) in RCA: 81] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 04/27/2020] [Indexed: 12/23/2022] Open
Abstract
2D van der Waals ferroelectrics have emerged as an attractive building block with immense potential to provide multifunctionality in nanoelectronics. Although several accomplishments have been reported in ferroelectric switching for out-of-plane ferroelectrics down to the monolayer, a purely in-plane ferroelectric has not been experimentally validated at the monolayer thickness. Herein, an in-plane ferroelectricity is demonstrated for micrometer-size monolayer SnS at room temperature. SnS has been commonly regarded to exhibit the odd–even effect, where the centrosymmetry breaks only in the odd-number layers to exhibit ferroelectricity. Remarkably, however, a robust room temperature ferroelectricity exists in SnS below a critical thickness of 15 layers with both an odd and even number of layers, suggesting the possibility of controlling the stacking sequence of multilayer SnS beyond the limit of ferroelectricity in the monolayer. This work will pave the way for nanoscale ferroelectric applications based on SnS as a platform for in-plane ferroelectrics. Out-of-plane ferroelectricity is usually unstable in the two dimensional limit due to the presence of the depolarization field. Here, the authors successfully circumvent this issue by growing µm-sized SnS monolayers that exhibit in-plane ferroelectricity that is stable at room temperature.
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Affiliation(s)
- Naoki Higashitarumizu
- Department of Materials Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-8656, Japan
| | - Hayami Kawamoto
- Department of Materials Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-8656, Japan
| | - Chien-Ju Lee
- Department of Electrophysics, National Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Bo-Han Lin
- Department of Electrophysics, National Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Fu-Hsien Chu
- Department of Electrophysics, National Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Itsuki Yonemori
- Department of Nanotechnology for Sustainable Energy, School of Science and Technology, Kwansei Gakuin University, Gakuen 2-1, Sanda, Hyogo, 669-1337, Japan
| | - Tomonori Nishimura
- Department of Materials Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-8656, Japan
| | - Katsunori Wakabayashi
- Department of Nanotechnology for Sustainable Energy, School of Science and Technology, Kwansei Gakuin University, Gakuen 2-1, Sanda, Hyogo, 669-1337, Japan
| | - Wen-Hao Chang
- Department of Electrophysics, National Chiao Tung University, Hsinchu, 30010, Taiwan.,Center for Emergent Functional Matter Science (CEFMS), National Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Kosuke Nagashio
- Department of Materials Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-8656, Japan.
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10
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Chi X, Wang H, Guo R, Whitcher TJ, Yu X, Yang P, Yan X, Breese MBH, Loh KP, Chen J, Rusydi A. Unusual Hole and Electron Midgap States and Orbital Reconstructions Induced Huge Ferroelectric Tunneling Electroresistance in BaTiO 3/SrTiO 3. NANO LETTERS 2020; 20:1101-1109. [PMID: 31944125 DOI: 10.1021/acs.nanolett.9b04390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Oxide heterostructures have attracted a lot of interest because of their rich exotic phenomena and potential applications. Recently, a greatly enhanced tunneling electroresistance (TER) of ferroelectric tunnel junctions (FTJs) has been realized in such heterostructures. However, our understanding on the electronic structure of resistance response with polarization reversal and the origin of huge TER is still lacking. Here, we report on electronic structures, particularly at the interface and surface, and the control of the spontaneous polarization of BaTiO3 films by changing the termination of a SrTiO3 substrate. Interestingly, unusual electron and hole midgap states are concurrently formed and accompanied by orbital reconstructions, which determine the ferroelectric polarization orientation in the BaTiO3/SrTiO3. Such unusual midgap states, which yield a strong electronic screening effect, reduce the ferroelectric barrier width and height, and pin the ferroelectric polarization, lead to a dramatic enhancement of the TER effect. The midgap states are also observed in BaTiO3 films on electron-doped Nb/SrTiO3 revealing its universality. Our result provides new insight into the origin of the huge TER effect and opens a new route for designing ferroelectric tunnel junction-based devices with huge TER through interface engineering.
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Affiliation(s)
- Xiao Chi
- Singapore Synchrotron Light Source , National University of Singapore , 5 Research Link, 117603 , Singapore
- Department of Chemistry , National University of Singapore , 3 Science Drive 3, 117543 , Singapore
- Center for Advanced 2D Materials and Graphene Research Centre , 2 Science Drive 2, 117526 , Singapore
| | - Han Wang
- Department of Materials Science and Engineering , National University of Singapore , 117575 , Singapore
| | - Rui Guo
- Department of Materials Science and Engineering , National University of Singapore , 117575 , Singapore
| | - Thomas J Whitcher
- Singapore Synchrotron Light Source , National University of Singapore , 5 Research Link, 117603 , Singapore
- Center for Advanced 2D Materials and Graphene Research Centre , 2 Science Drive 2, 117526 , Singapore
| | - Xiaojiang Yu
- Singapore Synchrotron Light Source , National University of Singapore , 5 Research Link, 117603 , Singapore
| | - Ping Yang
- Singapore Synchrotron Light Source , National University of Singapore , 5 Research Link, 117603 , Singapore
| | - Xiaobing Yan
- Department of Materials Science and Engineering , National University of Singapore , 117575 , Singapore
| | - Mark B H Breese
- Singapore Synchrotron Light Source , National University of Singapore , 5 Research Link, 117603 , Singapore
- Department of Physics , National University of Singapore , 2 Science Drive 3, 117542 , Singapore
| | - Kian Ping Loh
- Department of Chemistry , National University of Singapore , 3 Science Drive 3, 117543 , Singapore
- Center for Advanced 2D Materials and Graphene Research Centre , 2 Science Drive 2, 117526 , Singapore
- Solar Energy Research Institute of Singapore (SERIS) , 7 Engineering Drive 1, 117574 , Singapore
| | - Jingsheng Chen
- Department of Chemistry , National University of Singapore , 3 Science Drive 3, 117543 , Singapore
| | - Andrivo Rusydi
- Singapore Synchrotron Light Source , National University of Singapore , 5 Research Link, 117603 , Singapore
- Department of Physics , National University of Singapore , 2 Science Drive 3, 117542 , Singapore
- Center for Advanced 2D Materials and Graphene Research Centre , 2 Science Drive 2, 117526 , Singapore
- Solar Energy Research Institute of Singapore (SERIS) , 7 Engineering Drive 1, 117574 , Singapore
- NUSSNI-NanoCore , National University of Singapore , 117576 , Singapore
- Graduate School for Integrative Sciences and Engineering (NGS) , National University of Singapore , 28 Medical Drive, 117456 , Singapore
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11
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Li L, Liu X, He C, Wang S, Ji C, Zhang X, Sun Z, Zhao S, Hong M, Luo J. A Potential Sn-Based Hybrid Perovskite Ferroelectric Semiconductor. J Am Chem Soc 2020; 142:1159-1163. [DOI: 10.1021/jacs.9b11341] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Lina Li
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China
| | - Xitao Liu
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China
| | - Chao He
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China
| | - Sasa Wang
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chengmin Ji
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China
| | - Xinyuan Zhang
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhihua Sun
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China
| | - Sangen Zhao
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China
| | - Maochun Hong
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China
| | - Junhua Luo
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China
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