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Zheng J, Shi W, Li Z, Zhang J, Yang CY, Zhu Z, Wang M, Zhang J, Han F, Zhang H, Chen Y, Hu F, Shen B, Chen Y, Sun J. Charge-Transfer-Induced Interfacial Ferromagnetism in Ferromagnet-Free Oxide Heterostructures. ACS NANO 2024; 18:9232-9241. [PMID: 38466082 DOI: 10.1021/acsnano.4c01910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Due to the strong interlayer coupling between multiple degrees of freedom, oxide heterostructures have demonstrated exotic properties that are not shown by their bulk counterparts. One of the most interesting properties is ferromagnetism at the interface formed between "nonferromagnetic" compounds. Here we report on the interfacial ferromagnetic phase induced in the superlattices consisting of the two paramagnetic oxides CaRuO3 (CRO) and LaNiO3 (LNO). By varying the sublayer thickness in the superlattice period, we demonstrate that the ferromagnetic order has been established in both CaRuO3 and LaNiO3 sublayers, exhibiting an identical Curie temperature of ∼75 K. The X-ray absorption spectra suggest a strong charge transfer from Ru to Ni at the interface, triggering superexchange interactions between Ru/Ni ions and giving rise to the emergent ferromagnetic phase. Moreover, the X-ray linear dichroism spectra reveal the preferential occupancy of the d3z2-r2 orbital for the Ru ions and the dx2-y2 orbital for the Ni ions in the heterostructure. This leads to different magnetic anisotropy of the superlattices when they are dominated by CRO or LNO sublayers. This work clearly demonstrates a charge-transfer-induced interfacial ferromagnetic phase in the whole ferromagnet-free oxide heterostructures, offering a feasible way to tailor oxide materials for desired functionalities.
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Affiliation(s)
- Jie Zheng
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Wenxiao Shi
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Zhe Li
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Jing Zhang
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, People's Republic of China
| | - Chao-Yao Yang
- Department of Materials Science and Engineering, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan
| | - Zhaozhao Zhu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Mengqin Wang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Jine Zhang
- School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, People's Republic of China
| | - Furong Han
- School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, People's Republic of China
| | - Hui Zhang
- School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, People's Republic of China
| | - Yunzhong Chen
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Fengxia Hu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Baogen Shen
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
- Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201, People's Republic of China
| | - Yuansha Chen
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Jirong Sun
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
- Spintronics Institute, School of Physics and Technology, University of Jinan, Jinan 250022, China
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2
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Wang M, Zhu T, Bai H, Yin Z, Xu H, Shi W, Li Z, Zheng J, Gan Y, Chen Y, Shen B, Chen Y, Zhang Q, Hu F, Sun JR. Layered Ferromagnetic Structure Caused by the Proximity Effect and Interlayer Charge Transfer for LaNiO 3/LaMnO 3 Superlattices. NANO LETTERS 2024; 24:1122-1129. [PMID: 38230636 DOI: 10.1021/acs.nanolett.3c03658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2024]
Abstract
Magnetic proximity-induced magnetism in paramagnetic LaNiO3 (LNO) has spurred intensive investigations in the past decade. However, no consensus has been reached so far regarding the magnetic order in LNO layers in relevant heterostructures. This paper reports a layered ferromagnetic structure for the (111)-oriented LNO/LaMnO3 (LMO) superlattices. It is found that each period of the superlattice consisted of an insulating LNO-interfacial phase (five unit cells in thickness, ∼1.1 nm), a metallic LNO-inner phase, a poorly conductive LMO-interfacial phase (three unit cells in thickness, ∼0.7 nm), and an insulating LMO-inner phase. All four of these phases are ferromagnetic, showing different magnetizations. The Mn-to-Ni interlayer charge transfer is responsible for the emergence of a layered magnetic structure, which may cause magnetic interaction across the LNO/LMO interface and double exchange within the LMO-interfacial layer. This work indicates that the proximity effect is an effective means of manipulating the magnetic state and associated properties of complex oxides.
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Affiliation(s)
- Mengqin Wang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tao Zhu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Spallation Neutron Source Science Center, Dongguan 523803, China
| | - He Bai
- Spallation Neutron Source Science Center, Dongguan 523803, China
- Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
| | - Zhuo Yin
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hao Xu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wenxiao Shi
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhe Li
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jie Zheng
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yulin Gan
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yunzhong Chen
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Baogen Shen
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201, China
| | - Yuansha Chen
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qinghua Zhang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Fengxia Hu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Ji-Rong Sun
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- School of Materials Science & Engineering, Taiyuan University of Science and Technology, Taiyuan 030024, China
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3
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Shao M, Liu H, He R, Li X, Wu L, Ma J, Ye C, Hu X, Zhao R, Zhong Z, Yu Y, Wan C, Yang Y, Nan CW, Bai X, Ren TL, Renshaw Wang X. Programmable Ferroelectricity in Hf 0.5Zr 0.5O 2 Enabled by Oxygen Defect Engineering. NANO LETTERS 2024; 24:1231-1237. [PMID: 38251914 DOI: 10.1021/acs.nanolett.3c04104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2024]
Abstract
Ferroelectricity, especially the Si-compatible type recently observed in hafnia-based materials, is technologically useful for modern memory and logic applications, but it is challenging to differentiate intrinsic ferroelectric polarization from the polar phase and oxygen vacancy. Here, we report electrically controllable ferroelectricity in a Hf0.5Zr0.5O2-based heterostructure with Sr-doped LaMnO3, a mixed ionic-electronic conductor, as an electrode. Electrically reversible extraction and insertion of an oxygen vacancy into Hf0.5Zr0.5O2 are macroscopically characterized and atomically imaged in situ. Utilizing this reversible process, we achieved multilevel polarization states modulated by the electric field. Our study demonstrates the usefulness of the mixed conductor to repair, create, manipulate, and utilize advanced ferroelectric functionality. Furthermore, the programmed ferroelectric heterostructures with Si-compatible doped hafnia are desirable for the development of future ferroelectric electronics.
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Affiliation(s)
- Minghao Shao
- Institute of Microelectronics and Beijing National Research Center for Information Science and Technology (BNRist), Tsinghua University, Beijing 100084, China
| | - Houfang Liu
- Institute of Microelectronics and Beijing National Research Center for Information Science and Technology (BNRist), Tsinghua University, Beijing 100084, China
| | - Ri He
- Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Xiaomei Li
- School of Integrated Circuits, East China Normal University, Shanghai 200241, China
| | - Liang Wu
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
- Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093, China
| | - Ji Ma
- Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093, China
| | - Chen Ye
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| | - Xiangchen Hu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Ruiting Zhao
- Institute of Microelectronics and Beijing National Research Center for Information Science and Technology (BNRist), Tsinghua University, Beijing 100084, China
| | - Zhicheng Zhong
- Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Yi Yu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Caihua Wan
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Yi Yang
- Institute of Microelectronics and Beijing National Research Center for Information Science and Technology (BNRist), Tsinghua University, Beijing 100084, China
| | - Ce-Wen Nan
- School of Materials Science and Engineering, State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, Beijing 100084, China
| | - Xuedong Bai
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Tian-Ling Ren
- Institute of Microelectronics and Beijing National Research Center for Information Science and Technology (BNRist), Tsinghua University, Beijing 100084, China
| | - X Renshaw Wang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798
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4
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Shi W, Zheng J, Li Z, Wang M, Zhu Z, Zhang J, Zhang H, Chen Y, Hu F, Shen B, Chen Y, Sun J. Enhancing Interfacial Ferromagnetism and Magnetic Anisotropy of CaRuO 3 /SrTiO 3 Superlattices via Substrate Orientation. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023:e2308172. [PMID: 38037707 DOI: 10.1002/smll.202308172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 11/02/2023] [Indexed: 12/02/2023]
Abstract
Artificial oxide heterostructures have provided promising platforms for the exploration of emergent quantum phases with extraordinary properties. One of the most interesting phenomena is the interfacial magnetism formed between two non-magnetic compounds. Here, a robust ferromagnetic phase emerged at the (111)-oriented heterointerface between paramagnetic CaRuO3 and diamagnetic SrTiO3 is reported. The Curie temperature is as high as ≈155 K and the saturation magnetization is as large as ≈1.3 µB per formula unit for the (111)-CaRuO3 /SrTiO3 superlattices, which are obviously superior to those of the (001)-oriented counterparts and are comparable to the typical itinerant ferromagnet SrRuO3 . A strong in-plane magnetic anisotropy with six-fold symmetry is further revealed by the anisotropic magnetoresistance measurements, presenting a large in-plane anisotropic field of 3.0-3.6 T. More importantly, the magnetic easy axis of the (111)-oriented superlattices can be effectively tuned from 〈11 2 ¯ $11\overline{2}$ 1〉 to 〈1 1 ¯ 0 $1 \bar{1}0$ 〉 directions by increasing the layer thickness of SrTiO3 . The findings demonstrate a feasible approach to enhance the interface coupling effect by varying the stacking orientation of oxide heterostructures. The tunable magnetic anisotropy also shows potential applications in low-power-consumption or exchange spring devices.
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Affiliation(s)
- Wenxiao Shi
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jie Zheng
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhe Li
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Mengqin Wang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhaozhao Zhu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jine Zhang
- School of Integrated Circuit Science and Engineering, Beihang University, Beijing, 100191, China
| | - Hui Zhang
- School of Integrated Circuit Science and Engineering, Beihang University, Beijing, 100191, China
| | - Yunzhong Chen
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Fengxia Hu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Baogen Shen
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang, 315201, China
| | - Yuansha Chen
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jirong Sun
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
- Spintronics Institute, University of Jinan, Jinan, Shandong, 250022, China
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5
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Koussir H, Chernukha Y, Sthioul C, Haber E, Peric N, Biadala L, Capiod P, Berthe M, Lefebvre I, Wallart X, Grandidier B, Diener P. Large-Area Epitaxial Mott Insulating 1T-TaSe 2 Monolayer on GaP(111)B. NANO LETTERS 2023; 23:9413-9419. [PMID: 37820373 DOI: 10.1021/acs.nanolett.3c02813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/13/2023]
Abstract
Two-dimensional Mott materials have recently been reported in the dichalcogenide family with high potential for Mottronic applications. Nevertheless, their widespread use as a single or few layers is hampered by their limited device integration resulting from their growth on graphene, a metallic substrate. Here, we report on the fabrication of 1T-TaSe2 monolayers grown by molecular beam epitaxy on semiconducting gallium phosphide substrates. At the nanoscale, the charge density wave reconstruction and a moiré pattern resulting from the monolayer interaction with the substrate are observed by scanning tunneling microscopy. The fully open gap unveiled by tunneling spectroscopy, which can be further manipulated by the proximity of a metal tip, is confirmed by transport measurements from micrometric to millimetric scales, demonstrating a robust Mott insulating phase at up to 400 K.
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Affiliation(s)
- H Koussir
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, Junia-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - Y Chernukha
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, Junia-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - C Sthioul
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, Junia-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - E Haber
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, Junia-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - N Peric
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, Junia-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - L Biadala
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, Junia-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - P Capiod
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, Junia-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - M Berthe
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, Junia-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - I Lefebvre
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, Junia-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - X Wallart
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, Junia-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - B Grandidier
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, Junia-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
| | - P Diener
- Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, Junia-ISEN, UMR 8520 - IEMN, F-59000 Lille, France
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6
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Gauquelin N, Forte F, Jannis D, Fittipaldi R, Autieri C, Cuono G, Granata V, Lettieri M, Noce C, Miletto-Granozio F, Vecchione A, Verbeeck J, Cuoco M. Pattern Formation by Electric-Field Quench in a Mott Crystal. NANO LETTERS 2023; 23:7782-7789. [PMID: 37200109 DOI: 10.1021/acs.nanolett.3c00574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The control of the Mott phase is intertwined with the spatial reorganization of the electronic states. Out-of-equilibrium driving forces typically lead to electronic patterns that are absent at equilibrium, whose nature is however often elusive. Here, we unveil a nanoscale pattern formation in the Ca2RuO4 Mott insulator. We demonstrate how an applied electric field spatially reconstructs the insulating phase that, uniquely after switching off the electric field, exhibits nanoscale stripe domains. The stripe pattern has regions with inequivalent octahedral distortions that we directly observe through high-resolution scanning transmission electron microscopy. The nanotexture depends on the orientation of the electric field; it is nonvolatile and rewritable. We theoretically simulate the charge and orbital reconstruction induced by a quench dynamics of the applied electric field providing clear-cut mechanisms for the stripe phase formation. Our results open the path for the design of nonvolatile electronics based on voltage-controlled nanometric phases.
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Affiliation(s)
- Nicolas Gauquelin
- Electron Microscopy for Materials Research (EMAT), Department of Physics, University of Antwerp, BE-2020 Antwerpen, Belgium
- NANOlab Center of Excellence, University of Antwerp, BE-2020 Antwerpen, Belgium
| | - Filomena Forte
- CNR-SPIN, I-84084 Fisciano, Salerno, Italy
- Dipartimento di Fisica "E.R. Caianiello", Università di Salerno, I-84084 Fisciano, Salerno, Italy
| | - Daen Jannis
- Electron Microscopy for Materials Research (EMAT), Department of Physics, University of Antwerp, BE-2020 Antwerpen, Belgium
- NANOlab Center of Excellence, University of Antwerp, BE-2020 Antwerpen, Belgium
| | - Rosalba Fittipaldi
- CNR-SPIN, I-84084 Fisciano, Salerno, Italy
- Dipartimento di Fisica "E.R. Caianiello", Università di Salerno, I-84084 Fisciano, Salerno, Italy
| | - Carmine Autieri
- International Research Centre MagTop, Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, PL-02668 Warsaw, Poland
| | - Giuseppe Cuono
- International Research Centre MagTop, Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, PL-02668 Warsaw, Poland
| | - Veronica Granata
- Dipartimento di Fisica "E.R. Caianiello", Università di Salerno, I-84084 Fisciano, Salerno, Italy
| | | | - Canio Noce
- CNR-SPIN, I-84084 Fisciano, Salerno, Italy
- Dipartimento di Fisica "E.R. Caianiello", Università di Salerno, I-84084 Fisciano, Salerno, Italy
| | - Fabio Miletto-Granozio
- CNR-SPIN, I-80126 Napoli, Italy
- Dipartimento di Fisica, Università di Napoli, I-80126 Napoli, Italy
| | - Antonio Vecchione
- CNR-SPIN, I-84084 Fisciano, Salerno, Italy
- Dipartimento di Fisica "E.R. Caianiello", Università di Salerno, I-84084 Fisciano, Salerno, Italy
| | - Johan Verbeeck
- Electron Microscopy for Materials Research (EMAT), Department of Physics, University of Antwerp, BE-2020 Antwerpen, Belgium
- NANOlab Center of Excellence, University of Antwerp, BE-2020 Antwerpen, Belgium
| | - Mario Cuoco
- CNR-SPIN, I-84084 Fisciano, Salerno, Italy
- Dipartimento di Fisica "E.R. Caianiello", Università di Salerno, I-84084 Fisciano, Salerno, Italy
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7
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Qin Y, Gao Y, Lv F, Huang F, Liu F, Zhong T, Cui Y, Tian X. Multilevel resistive switching memory in lead-free double perovskite La[Formula: see text]NiFeO[Formula: see text] films. DISCOVER NANO 2023; 18:107. [PMID: 37644377 PMCID: PMC10465475 DOI: 10.1186/s11671-023-03885-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Accepted: 08/08/2023] [Indexed: 08/31/2023]
Abstract
Dense and flat La[Formula: see text]NiFeO[Formula: see text] (LNFO) films were fabricated on the indium tin oxide-coated glass (ITO/glass) substrate by sol-gel method. The bipolar resistive switching behavior (BRS) could be maintained in 100 cycles and remained after 30 days, indicating that the LNFO-based RS device owned good memory stability. Surprisingly, the multilevel RS characteristics were firstly observed in the Au/LNFO/ITO/glass device. The high resistance states (HRSs) and low resistance state (LRS) with the maximum ratio of [Formula: see text] 500 could be remained stably in 900 s and 130 cycles, demonstrating the fine retention and endurance ability of this LNFO-based RS device. The BRS behavior of Au/LNFO/ITO/glass devices primarily obeyed the SCLC mechanism controlled by oxygen vacancies (OVs) dispersed in the LNFO layer. Under the external electric field, injected electrons were captured or discharged by OVs during trapping or detrapping process in the LNFO layer. Thus, the resistive state switched between HRS and LRS reversibly. Moreover, the modulation of Schottky-like barrier formed at the Au/LNFO interface was contributed to the resistive states switchover. It was related to the change in OVs located at the dissipative region near the Au/LNFO interface. The multilevel RS ability of LNFO-based devices in this work provides an opportunity for researching deeply on the high density RS memory in lead-free double perovskite oxides-based devices.
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Affiliation(s)
- Yongfu Qin
- College of Physical Science and Technology and Guangxi Key Laboratory of Nuclear Physics and Technology, Guangxi Normal University, Yucai Road, Guilin, 541000 China
| | - Yuan Gao
- College of Physical Science and Technology and Guangxi Key Laboratory of Nuclear Physics and Technology, Guangxi Normal University, Yucai Road, Guilin, 541000 China
| | - Fengzhen Lv
- College of Physical Science and Technology and Guangxi Key Laboratory of Nuclear Physics and Technology, Guangxi Normal University, Yucai Road, Guilin, 541000 China
| | - Fangfang Huang
- College of Physical Science and Technology and Guangxi Key Laboratory of Nuclear Physics and Technology, Guangxi Normal University, Yucai Road, Guilin, 541000 China
| | - Fuchi Liu
- College of Physical Science and Technology and Guangxi Key Laboratory of Nuclear Physics and Technology, Guangxi Normal University, Yucai Road, Guilin, 541000 China
| | - Tingting Zhong
- College of Physical Science and Technology and Guangxi Key Laboratory of Nuclear Physics and Technology, Guangxi Normal University, Yucai Road, Guilin, 541000 China
| | - Yuhang Cui
- College of Physical Science and Technology and Guangxi Key Laboratory of Nuclear Physics and Technology, Guangxi Normal University, Yucai Road, Guilin, 541000 China
| | - Xuedong Tian
- College of Physical Science and Technology and Guangxi Key Laboratory of Nuclear Physics and Technology, Guangxi Normal University, Yucai Road, Guilin, 541000 China
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8
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Erpenbeck A, Gull E, Cohen G. Quantum Monte Carlo Method in the Steady State. PHYSICAL REVIEW LETTERS 2023; 130:186301. [PMID: 37204908 DOI: 10.1103/physrevlett.130.186301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 12/07/2022] [Accepted: 04/07/2023] [Indexed: 05/21/2023]
Abstract
We present a numerically exact steady-state inchworm Monte Carlo method for nonequilibrium quantum impurity models. Rather than propagating an initial state to long times, the method is directly formulated in the steady state. This eliminates any need to traverse the transient dynamics and grants access to a much larger range of parameter regimes at vastly reduced computational costs. We benchmark the method on equilibrium Green's functions of quantum dots in the noninteracting limit and in the unitary limit of the Kondo regime. We then consider correlated materials described with dynamical mean field theory and driven away from equilibrium by a bias voltage. We show that the response of a correlated material to a bias voltage differs qualitatively from the splitting of the Kondo resonance observed in bias-driven quantum dots.
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Affiliation(s)
- A Erpenbeck
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - E Gull
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - G Cohen
- The Raymond and Beverley Sackler Center for Computational Molecular and Materials Science, Tel Aviv University, Tel Aviv 6997801, Israel
- School of Chemistry, Tel Aviv University, Tel Aviv 6997801, Israel
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9
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Teruya R, Sato T, Yamashita M, Hanasaki N, Ueda A, Matsuda M. Reversible Insulator–Metal Transition by Chemical Doping and Dedoping of a Mott Insulator. Angew Chem Int Ed Engl 2022; 61:e202206428. [DOI: 10.1002/anie.202206428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Indexed: 11/12/2022]
Affiliation(s)
- Ryota Teruya
- Department of Chemistry Graduate School of Science and Technology Kumamoto University 2-39-1 Kurokami Chuo-ku, Kumamoto 860-8555 Japan
| | - Tetsu Sato
- Department of Chemistry Graduate School of Science Tohoku University 6-3 Aramaki-Aza-Aoba Aoba-ku, Sendai 980-8578 Japan
| | - Masahiro Yamashita
- Department of Chemistry Graduate School of Science Tohoku University 6-3 Aramaki-Aza-Aoba Aoba-ku, Sendai 980-8578 Japan
| | - Noriaki Hanasaki
- Department of Physics Graduate School of Science Osaka University 1-1 Machikaneyama Toyonaka, Osaka 560-0043 Japan
| | - Akira Ueda
- Department of Chemistry Graduate School of Science and Technology Kumamoto University 2-39-1 Kurokami Chuo-ku, Kumamoto 860-8555 Japan
| | - Masaki Matsuda
- Department of Chemistry Graduate School of Science and Technology Kumamoto University 2-39-1 Kurokami Chuo-ku, Kumamoto 860-8555 Japan
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10
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Lee YJ, Hong K, Na K, Yang J, Lee TH, Kim B, Bark CW, Kim JY, Park SH, Lee S, Jang HW. Nonvolatile Control of Metal-Insulator Transition in VO 2 by Ferroelectric Gating. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2203097. [PMID: 35713476 DOI: 10.1002/adma.202203097] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 06/09/2022] [Indexed: 06/15/2023]
Abstract
Controlling phase transitions in correlated materials yields emergent functional properties, providing new aspects to future electronics and a fundamental understanding of condensed matter systems. With vanadium dioxide (VO2 ), a representative correlated material, an approach to control a metal-insulator transition (MIT) behavior is developed by employing a heteroepitaxial structure with a ferroelectric BiFeO3 (BFO) layer to modulate the interaction of correlated electrons. Owing to the defect-alleviated interfaces, the enhanced coupling between the correlated electrons and ferroelectric polarization is successfully demonstrated by showing a nonvolatile control of MIT of VO2 at room temperature. The ferroelectrically-tunable MIT can be realized through the Mott transistor (VO2 /BFO/SrRuO3 ) with a remanent polarization of 80 µC cm-2 , leading to a nonvolatile MIT behavior through the reversible electrical conductance with a large on/off ratio (≈102 ), long retention time (≈104 s), and high endurance (≈103 cycles). Furthermore, the structural phase transition of VO2 is corroborated by ferroelectric polarization through in situ Raman mapping analysis. This study provides novel design principles for heteroepitaxial correlated materials and innovative insight to modulate multifunctional properties.
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Affiliation(s)
- Yoon Jung Lee
- Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Seoul, 08826, Republic of Korea
| | - Kootak Hong
- Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Seoul, 08826, Republic of Korea
- Department of Material Science and Engineering, Chonnam National University, Gwangju, 61186, Republic of Korea
| | - Kyeongho Na
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, 61005, Republic of Korea
| | - Jiwoong Yang
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, 61005, Republic of Korea
| | - Tae Hyung Lee
- Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Seoul, 08826, Republic of Korea
| | - Byungsoo Kim
- Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Seoul, 08826, Republic of Korea
| | - Chung Wung Bark
- Department of Electrical Engineering, Gachon University, Seongnam-si, Gyeonggi-do, 13120, South Korea
| | - Jae Young Kim
- Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Seoul, 08826, Republic of Korea
| | - Sung Hyuk Park
- Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Seoul, 08826, Republic of Korea
| | - Sanghan Lee
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, 61005, Republic of Korea
| | - Ho Won Jang
- Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Seoul, 08826, Republic of Korea
- Advanced Institute of Convergence Technology, Seoul National University, Suwon, 16229, Republic of Korea
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11
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Teruya R, Sato T, Yamashita M, Hanasaki N, Ueda A, Matsuda M. Reversible Insulator–Metal Transition by Chemical Doping and Dedoping of a Mott Insulator. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202206428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Ryota Teruya
- Kumamoto University: Kumamoto Daigaku Chemistry JAPAN
| | - Tetsu Sato
- Tohoku University: Tohoku Daigaku Chemistry JAPAN
| | | | | | - Akira Ueda
- Kumamoto University: Kumamoto Daigaku Chemistry JAPAN
| | - Masaki Matsuda
- Kumamoto University Chemistry Kurokami 2-39-1 860-8555 Kumamoto JAPAN
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12
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Combinatorial synthesis of heteroepitaxial, multi-cation, thin-films via pulsed laser deposition coupled with in-situ, chemical and structural characterization. Sci Rep 2022; 12:3219. [PMID: 35256630 PMCID: PMC8901668 DOI: 10.1038/s41598-022-06955-5] [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: 09/22/2021] [Accepted: 02/07/2022] [Indexed: 11/09/2022] Open
Abstract
AbstractCombinatorial synthesis via a continuous composition spread is an excellent route to develop thin-film libraries as it is both time- and cost-efficient. Creating libraries of functional, multicomponent, complex oxide films requires excellent control over the synthesis parameters combined with high-throughput analytical feedback. A reliable, high-throughput, in-situ characterization analysis method is required to meet the crucial need to rapidly screen materials libraries. Here, we report on the combination of two in-situ techniques—(a) Reflection high-energy electron diffraction (RHEED) for heteroepitaxial characterization and a newly developed compositional analysis technique, low-angle x-ray spectroscopy (LAXS), to map the chemical composition profile of combinatorial heteroepitaxial complex oxide films deposited using a continuous composition spread method via pulsed laser deposition. This is accomplished using a unique state-of-the-art combinatorial growth system with a fully synchronized four-axis mechanical substrate stage without shadow masks, alternating acquisition of chemical compositional data using LAXS at various different positions on the $$\sim$$
∼
41 mm $$\times$$
×
41 mm range and sequential deposition of multilayers of SrTiO$$_3$$
3
and $$\hbox {SrTi}_{0.8}\hbox {Ru}_{0.2}\hbox {O}_3$$
SrTi
0.8
Ru
0.2
O
3
on a 2-inch (50.8 mm) $$\hbox {LaAlO}_3$$
LaAlO
3
wafer in a single growth run. Rutherford backscattering spectrometry (RBS) is used to calibrate and validate the compositions determined by LAXS. This study shows the feasibility of combinatorial synthesis of heteroepitaxial, functional complex oxide films at wafer-scale via two essential in-situ characterization tools—RHEED for structural analysis or heteroepitaxy and LAXS for compositional characterization. This is a powerful technique for development of new films with optimized heteroepitaxy and composition.
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13
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Resonant tunneling driven metal-insulator transition in double quantum-well structures of strongly correlated oxide. Nat Commun 2021; 12:7070. [PMID: 34862386 PMCID: PMC8642393 DOI: 10.1038/s41467-021-27327-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 11/12/2021] [Indexed: 11/09/2022] Open
Abstract
The metal-insulator transition (MIT), a fascinating phenomenon occurring in some strongly correlated materials, is of central interest in modern condensed-matter physics. Controlling the MIT by external stimuli is a key technological goal for applications in future electronic devices. However, the standard control by means of the field effect, which works extremely well for semiconductor transistors, faces severe difficulties when applied to the MIT. Hence, a radically different approach is needed. Here, we report an MIT induced by resonant tunneling (RT) in double quantum well (QW) structures of strongly correlated oxides. In our structures, two layers of the strongly correlated conductive oxide SrVO3 (SVO) sandwich a barrier layer of the band insulator SrTiO3. The top QW is a marginal Mott-insulating SVO layer, while the bottom QW is a metallic SVO layer. Angle-resolved photoemission spectroscopy experiments reveal that the top QW layer becomes metallized when the thickness of the tunneling barrier layer is reduced. An analysis based on band structure calculations indicates that RT between the quantized states of the double QW induces the MIT. Our work opens avenues for realizing the Mott-transistor based on the wave-function engineering of strongly correlated electrons.
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14
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Zhang Q, Hou Y, Zhang T, Xu Z, Huang Z, Yuan P, Jia L, Yang H, Huang Y, Ji W, Qiao J, Wu X, Wang Y. Visualizing Spatial Evolution of Electron-Correlated Interface in Two-Dimensional Heterostructures. ACS NANO 2021; 15:16589-16596. [PMID: 34606233 DOI: 10.1021/acsnano.1c06332] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Microscopically visualizing the evolution of electronic structures at the interface between two electron-correlated domains shows fundamental importance in both material science and physics. Here, we report scanning tunneling microscopy and spectroscopy studies of the interfacial electronic structures evolution in a phase-engineered monolayer NbSe2 heterostructure. The H-NbSe2 metallic state penetrates the Mott insulating T-NbSe2 at the H/T phase interface, with a prominent 2D charge density wave (CDW) proximity effect. Moreover, an insulating Mott gap collapse with the disappearance of the upper Hubbard band is detected at the electronic phase transition region. Theoretical calculations reveal that such insulating Mott gap collapse can be attributed to the electron doping effect induced by the interface. Our findings promote a microscopical understanding of the interactions between different electron-correlated systems and provide an effective method for controlling the Mott insulating states with phase engineering.
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Affiliation(s)
- Quanzhen Zhang
- MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, School of Integrated Circuits and Electronics, Beijing Institute of Technology, Beijing 100081, China
| | - Yanhui Hou
- MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, School of Integrated Circuits and Electronics, Beijing Institute of Technology, Beijing 100081, China
| | - Teng Zhang
- MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, School of Integrated Circuits and Electronics, Beijing Institute of Technology, Beijing 100081, China
| | - Ziqiang Xu
- MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, School of Integrated Circuits and Electronics, Beijing Institute of Technology, Beijing 100081, China
| | - Zeping Huang
- MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, School of Integrated Circuits and Electronics, Beijing Institute of Technology, Beijing 100081, China
| | - Peiwen Yuan
- MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, School of Integrated Circuits and Electronics, Beijing Institute of Technology, Beijing 100081, China
| | - Liangguang Jia
- MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, School of Integrated Circuits and Electronics, Beijing Institute of Technology, Beijing 100081, China
| | - Huixia Yang
- MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, School of Integrated Circuits and Electronics, Beijing Institute of Technology, Beijing 100081, China
| | - Yuan Huang
- MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, School of Integrated Circuits and Electronics, Beijing Institute of Technology, Beijing 100081, China
| | - Wei Ji
- Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-Nano Devices, Department of Physics, Renmin University of China, Beijing 100872, China
| | - Jingsi Qiao
- MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, School of Integrated Circuits and Electronics, Beijing Institute of Technology, Beijing 100081, China
- Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-Nano Devices, Department of Physics, Renmin University of China, Beijing 100872, China
| | - Xu Wu
- MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, School of Integrated Circuits and Electronics, Beijing Institute of Technology, Beijing 100081, China
| | - Yeliang Wang
- MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, School of Integrated Circuits and Electronics, Beijing Institute of Technology, Beijing 100081, China
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15
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Sohn B, Kim JR, Kim CH, Lee S, Hahn S, Kim Y, Huh S, Kim D, Kim Y, Kyung W, Kim M, Kim M, Noh TW, Kim C. Observation of metallic electronic structure in a single-atomic-layer oxide. Nat Commun 2021; 12:6171. [PMID: 34702805 PMCID: PMC8548526 DOI: 10.1038/s41467-021-26444-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 10/05/2021] [Indexed: 11/08/2022] Open
Abstract
Correlated electrons in transition metal oxides exhibit a variety of emergent phases. When transition metal oxides are confined to a single-atomic-layer thickness, experiments so far have shown that they usually lose diverse properties and become insulators. In an attempt to extend the range of electronic phases of the single-atomic-layer oxide, we search for a metallic phase in a monolayer-thick epitaxial SrRuO3 film. Combining atomic-scale epitaxy and angle-resolved photoemission measurements, we show that the monolayer SrRuO3 is a strongly correlated metal. Systematic investigation reveals that the interplay between dimensionality and electronic correlation makes the monolayer SrRuO3 an incoherent metal with orbital-selective correlation. Furthermore, the unique electronic phase of the monolayer SrRuO3 is found to be highly tunable, as charge modulation demonstrates an incoherent-to-coherent crossover of the two-dimensional metal. Our work emphasizes the potentially rich phases of single-atomic-layer oxides and provides a guide to the manipulation of their two-dimensional correlated electron systems.
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Affiliation(s)
- Byungmin Sohn
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Korea
| | - Jeong Rae Kim
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Korea
| | - Choong H Kim
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Korea
| | - Sangmin Lee
- Department of Materials Science and Engineering and Research Institute of Advanced Materials, Seoul National University, Seoul, 08826, Korea
| | - Sungsoo Hahn
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Korea
| | - Younsik Kim
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Korea
| | - Soonsang Huh
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Korea
| | - Donghan Kim
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Korea
| | - Youngdo Kim
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Korea
| | - Wonshik Kyung
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Korea
| | - Minsoo Kim
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Korea
| | - Miyoung Kim
- Department of Materials Science and Engineering and Research Institute of Advanced Materials, Seoul National University, Seoul, 08826, Korea
| | - Tae Won Noh
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Korea.
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Korea.
| | - Changyoung Kim
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Korea.
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Korea.
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16
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Behera BC, Sabat G, Bhat SG, Sarangi SN, Sekhar BR, Samal D. Tailoring magnetism in spinel vanadate CoV 2O 4epitaxial thin films. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:365801. [PMID: 34167093 DOI: 10.1088/1361-648x/ac0e6f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Accepted: 06/24/2021] [Indexed: 06/13/2023]
Abstract
Near itinerant cubic bulk CoV2O4is at variance with other spinel vanadates by not showing orbital ordering down to low temperature, albeit it displays fragile anomalies related to spin, and lattice structure, signaling a spin/orbital glass transition around 95 K. We investigate tetragonal-like epitaxial CoV2O4films on SrTiO3and (La0.3Sr0.7)(Al0.65Ta0.35)O3substrates that exhibit pronounced signature of spin reorientation transition from toa/bplane around 90 K unlike its bulk counterpart. Using in-plane and out-of-plane magnetic measurements, we demonstrate the intricate link between Co2+and V3+sublattice magnetizations that give rise to anisotropic magnetic switching. In-plane magnetic measurements reveal a wasp-waist shapedM(H) loop below reorientation transition temperature, while the out-of-plane follows antiferromagnet-likeM(H) response. The wasp-waist shaped feature could be linked to in-plane spin-canted (anti)ferromagnetism induced by canting away of V-spins away from antiferromagnetically coupled Co-spin direction below reorientation transition temperature. Further, we uncover the evidence for slow relaxation over a period of ∼104 s at 20 K and memory effect that indicates the possible existence for magnetic glassy phase in the low temperature regime. Using epitaxial strain as a control knob, our results inspire future study to manipulate orbital states, spin texture and itinerant electron character in tailored CoV2O4films away from cubic lattice symmetry.
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Affiliation(s)
- B C Behera
- Institute of Physics, Sachivalaya Marg, Bhubaneswar 751005, India
| | - G Sabat
- Institute of Physics, Sachivalaya Marg, Bhubaneswar 751005, India
- Homi Bhabha National Institute, Anushakti Nagar, Mumbai 400085, India
| | - Shwetha G Bhat
- Department of Physics, Indian Institute of Science, Bangalore 560012, India
| | - S N Sarangi
- Institute of Physics, Sachivalaya Marg, Bhubaneswar 751005, India
| | - B R Sekhar
- Institute of Physics, Sachivalaya Marg, Bhubaneswar 751005, India
- Homi Bhabha National Institute, Anushakti Nagar, Mumbai 400085, India
| | - D Samal
- Institute of Physics, Sachivalaya Marg, Bhubaneswar 751005, India
- Homi Bhabha National Institute, Anushakti Nagar, Mumbai 400085, India
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17
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Fu R, Wu Z, Pan Z, Gao Z, Li Z, Kong X, Li L. Fluorine-Induced Surface Metallization for Ammonia Synthesis under Photoexcitation up to 1550 nm. Angew Chem Int Ed Engl 2021; 60:11173-11179. [PMID: 33650282 DOI: 10.1002/anie.202100572] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 02/17/2021] [Indexed: 11/10/2022]
Abstract
The first observation of surface metallization of TiO2-x induced by fluoride ions is presented. The emerging metallic states are contributed by the 3d orbital of surface Ti and the 2p orbital of surface bridging F, which are intrinsically originated from the strong electron repulsion between F- and adjacent Ti3+ . The metalized TiO2-x with reduced work function and downward band bending possesses high electron-donating power to supported Ru species via atomic-scale ohmic contacts, exhibiting unprecedented photocatalytic performances for ammonia synthesis across the entire solar spectrum region (200-1550 nm) at room temperature. Mechanism and kinetic analysis revealed that the loaded Ru could behave as efficient electron sinks to accumulate photogenerated electrons and that the metallic surface markedly enhanced the dissociation of H2 and N2 by the hot electrons generated by the visible or even infrared light irradiation.
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Affiliation(s)
- Rong Fu
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun, 130012, P. R. China
| | - Zewen Wu
- College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China.,Centre for the Physics of Materials and Department of Physics, McGill University, Montreal, QC, H3A 2T8, Canada
| | - Ziye Pan
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun, 130012, P. R. China
| | - Zhuoyang Gao
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun, 130012, P. R. China
| | - Zhen Li
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun, 130012, P. R. China
| | - Xianghua Kong
- College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China.,Centre for the Physics of Materials and Department of Physics, McGill University, Montreal, QC, H3A 2T8, Canada
| | - Lu Li
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun, 130012, P. R. China.,Electron Microscopy Center, Jilin University, Changchun, 130012, P. R. China
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18
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Fluorine‐Induced Surface Metallization for Ammonia Synthesis under Photoexcitation up to 1550 nm. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202100572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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19
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Chang YW, Wu PC, Yi JB, Liu YC, Chou Y, Chou YC, Yang JC. A Fast Route Towards Freestanding Single-Crystalline Oxide Thin Films by Using YBa 2Cu 3O 7-x as a Sacrificial Layer. NANOSCALE RESEARCH LETTERS 2020; 15:172. [PMID: 32857192 PMCID: PMC7455685 DOI: 10.1186/s11671-020-03402-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 08/17/2020] [Indexed: 06/11/2023]
Abstract
Researchers have long been seeking multifunctional materials that can be adopted for next-generation nanoelectronics, and which, hopefully, are compatible with current semiconductor processing for further integration. Along this vein, complex oxides have gained numerous attention due to their versatile functionalities. Despite the fact that unbounded potential of complex oxides has been examined over the past years, one of the major challenges lies in the direct integration of these functional oxides onto existing devices or targeted substrates that are inherently incompatible in terms of oxide growth. To fulfill this goal, freestanding processes have been proposed, in which wet etching of inserted sacrificial layers is regarded as one of the most efficient ways to obtain epitaxial high-quality thin films. In this study, we propose using an alternative oxide, YBa2Cu3O7 (YCBO), as a sacrificial layer, which can be easily dissolved in light hydrochloric acid in a more efficient way, while protecting selected complex oxides intact. The high epitaxial quality of the selected complex oxide before and after freestanding process using YBCO as a sacrificial layer is comprehensively studied via a combination of atomic force microscopy, X-ray diffraction, transmission electron microscopy, and electrical transports. This approach enables direct integration of complex oxides with arbitrary substrates and devices and is expected to offer a faster route towards the development of low-dimensional quantum materials.
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Affiliation(s)
- Yao-Wen Chang
- Department of Physics, National Cheng Kung University, Tainan, 70101 Taiwan
| | - Ping-Chun Wu
- Department of Physics, National Cheng Kung University, Tainan, 70101 Taiwan
| | - Jhih-Bang Yi
- Department of Physics, National Cheng Kung University, Tainan, 70101 Taiwan
| | - Yu-Chen Liu
- Department of Physics, National Cheng Kung University, Tainan, 70101 Taiwan
| | - Yi Chou
- Department of Electrophysics, National Chiao Tung University, Hsinchu, 30010 Taiwan
| | - Yi-Chia Chou
- Department of Electrophysics, National Chiao Tung University, Hsinchu, 30010 Taiwan
| | - Jan-Chi Yang
- Department of Physics, National Cheng Kung University, Tainan, 70101 Taiwan
- Center for Quantum Frontiers of Research & Technology (QFort), National Cheng Kung University, Tainan, 70101 Taiwan
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20
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Tuning proton-coupled electron transfer by crystal orientation for efficient water oxidization on double perovskite oxides. Nat Commun 2020; 11:4299. [PMID: 32855418 PMCID: PMC7453016 DOI: 10.1038/s41467-020-17657-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 07/13/2020] [Indexed: 01/16/2023] Open
Abstract
Developing highly efficient and cost-effective oxygen evolution reaction (OER) electrocatalysts is critical for many energy devices. While regulating the proton-coupled electron transfer (PCET) process via introducing additive into the system has been reported effective in promoting OER activity, controlling the PCET process by tuning the intrinsic material properties remains a challenging task. In this work, we take double perovskite oxide PrBa0.5Sr0.5Co1.5Fe0.5O5+δ (PBSCF) as a model system to demonstrate enhancing OER activity through the promotion of PCET by tuning the crystal orientation and correlated proton diffusion. OER kinetics on PBSCF thin films with (100), (110), and (111) orientation, deposited on single crystal LaAlO3 substrates, were investigated using electrochemical measurements, density functional theory (DFT) calculations, and synchrotron-based near ambient X-ray photoelectron spectroscopy. The results clearly show that the OER activity and the ease of deprotonation depend on orientation and follow the order of (100) > (110) > (111). Correlated with OER activity, proton diffusion is found to be the fastest in the (100) film, followed by (110) and (111) films. Our results point out a way of boosting PCET and OER activity, which can also be successfully applied to a wide range of crucial applications in green energy and environment.
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Booth JM, Russo SP. Yang-Mills structure for electron-phonon interactions in vanadium dioxide. Sci Rep 2020; 10:12547. [PMID: 32719390 PMCID: PMC7385623 DOI: 10.1038/s41598-020-68958-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 06/01/2020] [Indexed: 11/16/2022] Open
Abstract
This work presents a method of grouping the electron spinors and the phonon modes of metal oxide crystals such as vanadium dioxide into an SU(2) gauge theory. The gauge "charge" is the electron spin, which is assumed to couple to the transverse acoustic phonons on the basis of spin ordering phenomena in [Formula: see text]- and [Formula: see text]-[Formula: see text], while the longitudinal mode is neutral. A generalization of the Peierls Mechanism is presented based on the discrete gauge invariance of crystals and the corresponding Ward-Takahashi identity. The introduction of a band index results in violation of this discrete Ward-Takahashi identity for interband transitions, resulting in scattering from the longitudinal component. Thus both the spinors and the bosons acquire mass and an electronic band gap and optical phonon modes result: a symmetry-breaking metal-insulator transition, which can manifest concurrent spin-ordering.
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Affiliation(s)
- Jamie M Booth
- ARC Centre of Excellence in Exciton Science, RMIT University, Melbourne, VIC, 3001, Australia.
- Theoretical Chemical and Quantum Physics, RMIT University, Melbourne, VIC, 3001, Australia.
| | - Salvy P Russo
- ARC Centre of Excellence in Exciton Science, RMIT University, Melbourne, VIC, 3001, Australia
- Theoretical Chemical and Quantum Physics, RMIT University, Melbourne, VIC, 3001, Australia
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22
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Nallagatla VR, Heisig T, Baeumer C, Feyer V, Jugovac M, Zamborlini G, Schneider CM, Waser R, Kim M, Jung CU, Dittmann R. Topotactic Phase Transition Driving Memristive Behavior. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1903391. [PMID: 31441160 DOI: 10.1002/adma.201903391] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 07/26/2019] [Indexed: 06/10/2023]
Abstract
Redox-based memristive devices are one of the most attractive candidates for future nonvolatile memory applications and neuromorphic circuits, and their performance is determined by redox processes and the corresponding oxygen-ion dynamics. In this regard, brownmillerite SrFeO2.5 has been recently introduced as a novel material platform due to its exceptional oxygen-ion transport properties for resistive-switching memory devices. However, the underlying redox processes that give rise to resistive switching remain poorly understood. By using X-ray absorption spectromicroscopy, it is demonstrated that the reversible redox-based topotactic phase transition between the insulating brownmillerite phase, SrFeO2.5 , and the conductive perovskite phase, SrFeO3 , gives rise to the resistive-switching properties of SrFeOx memristive devices. Furthermore, it is found that the electric-field-induced phase transition spreads over a large area in (001) oriented SrFeO2.5 devices, where oxygen vacancy channels are ordered along the in-plane direction of the device. In contrast, (111)-grown SrFeO2.5 devices with out-of-plane oriented oxygen vacancy channels, reaching from the bottom to the top electrode, show a localized phase transition. These findings provide detailed insight into the resistive-switching mechanism in SrFeOx -based memristive devices within the framework of metal-insulator topotactic phase transitions.
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Affiliation(s)
- Venkata R Nallagatla
- Peter Gruenberg Institute, Forschungszentrum Juelich GmbH and JARA-FIT, 52425, Juelich, Germany
- Department of Physics and Oxide Research Centre, Hankuk University of Foreign Studies, Yongin, 17035, South Korea
| | - Thomas Heisig
- Peter Gruenberg Institute, Forschungszentrum Juelich GmbH and JARA-FIT, 52425, Juelich, Germany
- Institute of Electronic Materials, IWE2, RWTH Aachen University, 52056, Aachen, Germany
| | - Christoph Baeumer
- Peter Gruenberg Institute, Forschungszentrum Juelich GmbH and JARA-FIT, 52425, Juelich, Germany
- Institute of Electronic Materials, IWE2, RWTH Aachen University, 52056, Aachen, Germany
| | - Vitaliy Feyer
- Peter Gruenberg Institute, Forschungszentrum Juelich GmbH and JARA-FIT, 52425, Juelich, Germany
- Fakultaet f. Physik and Center for Nanointegration Duisburg-Essen (CENIDE), Universitat Duisburg-Essen, 47048, Duisburg, Germany
| | - Matteo Jugovac
- Peter Gruenberg Institute, Forschungszentrum Juelich GmbH and JARA-FIT, 52425, Juelich, Germany
| | - Giovanni Zamborlini
- Peter Gruenberg Institute, Forschungszentrum Juelich GmbH and JARA-FIT, 52425, Juelich, Germany
- Technische Universitaet Dortmund, Experimentelle Physik VI, 44227, Dortmund, Germany
| | - Claus M Schneider
- Peter Gruenberg Institute, Forschungszentrum Juelich GmbH and JARA-FIT, 52425, Juelich, Germany
- Fakultaet f. Physik and Center for Nanointegration Duisburg-Essen (CENIDE), Universitat Duisburg-Essen, 47048, Duisburg, Germany
- Department of Physics, University of California, Davis, CA, 95616, USA
| | - Rainer Waser
- Peter Gruenberg Institute, Forschungszentrum Juelich GmbH and JARA-FIT, 52425, Juelich, Germany
- Institute of Electronic Materials, IWE2, RWTH Aachen University, 52056, Aachen, Germany
| | - Miyoung Kim
- Department of Material Science and Engineering and Research Institute of Advanced Materials, Seoul National University, Seoul, 08826, South Korea
| | - Chang Uk Jung
- Department of Physics and Oxide Research Centre, Hankuk University of Foreign Studies, Yongin, 17035, South Korea
| | - Regina Dittmann
- Peter Gruenberg Institute, Forschungszentrum Juelich GmbH and JARA-FIT, 52425, Juelich, Germany
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Effect of Functional Group on Electrical Switching Behaviour of an Imidazole Derivative in Langmuir‐Blodgett Film. ChemistrySelect 2019. [DOI: 10.1002/slct.201901824] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Large Scale Synthesis of Nanopyramidal-Like VO₂ Films by an Oxygen-Assisted Etching Growth Method with Significantly Enhanced Field Emission Properties. NANOMATERIALS 2019; 9:nano9040549. [PMID: 30987293 PMCID: PMC6523309 DOI: 10.3390/nano9040549] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 03/20/2019] [Accepted: 03/28/2019] [Indexed: 01/30/2023]
Abstract
The present investigation reported on a novel oxygen-assisted etching growth method that can directly transform wafer-scale plain VO₂ thin films into pyramidal-like VO₂ nanostructures with highly improved field-emission properties. The oxygen applied during annealing played a key role in the formation of the special pyramidal-like structures by introducing thin oxygen-rich transition layers on the top surfaces of the VO₂ crystals. An etching related growth and transformation mechanism for the synthesis of nanopyramidal films was proposed. Structural characterizations confirmed the formation of a composite VO₂ structure of monoclinic M1 (P21/c) and Mott insulating M2 (C2/m) phases for the films at room temperature. Moreover, by varying the oxygen concentration, the nanocrystal morphology of the VO₂ films could be tuned, ranging over pyramidal, dot, and/or twin structures. These nanopyramidal VO₂ films showed potential benefits for application such as temperature-regulated field emission devices. For one typical sample deposited on a 3-inch silicon substrate, its emission current (measured at 6 V/μm) increased by about 1000 times after the oxygen-etching treatment, and the field enhancement factor β reached as high as 3810 and 1620 for the M and R states, respectively. The simple method reported in the present study may provide a protocol for building a variety of large interesting surfaces for VO₂-based device applications.
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Jedrecy N, Aghavnian T, Moussy JB, Magnan H, Stanescu D, Portier X, Arrio MA, Mocuta C, Vlad A, Belkhou R, Ohresser P, Barbier A. Cross-Correlation between Strain, Ferroelectricity, and Ferromagnetism in Epitaxial Multiferroic CoFe 2O 4/BaTiO 3 Heterostructures. ACS APPLIED MATERIALS & INTERFACES 2018; 10:28003-28014. [PMID: 30085643 DOI: 10.1021/acsami.8b09499] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Multiferroic biphase systems with robust ferromagnetic and ferroelectric response at room temperature would be ideally suitable for voltage-controlled nonvolatile memories. Understanding the role of strain and charges at interfaces is central for an accurate control of the ferroelectricity as well as of the ferromagnetism. In this paper, we probe the relationship between the strain and the ferromagnetic/ferroelectric properties in the layered CoFe2O4/BaTiO3 (CFO/BTO) model system. For this purpose, ultrathin epitaxial bilayers, ranging from highly strained to fully relaxed, were grown by molecular beam epitaxy on Nb:SrTiO3(001). The lattice characteristics, determined by X-ray diffraction, evidence a non-intuitive cross-correlation: the strain in the bottom BTO layer depends on the thickness of the top CFO layer and vice versa. Plastic deformation participates in the relaxation process through dislocations at both interfaces, revealed by electron microscopy. Importantly, the switching of the BTO ferroelectric polarization, probed by piezoresponse force microscopy, is found dependent on the CFO thickness: the larger is the latter, the easiest is the BTO switching. In the thinnest thickness regime, the tetragonality of BTO and CFO has a strong impact on the 3d electronic levels of the different cations, which were probed by X-ray linear dichroism. The quantitative determination of the nature and repartition of the magnetic ions in CFO, as well as of their magnetic moments, has been carried out by X-ray magnetic circular dichroism, with the support of multiplet calculations. While bulklike ferrimagnetism is found for 5-15 nm thick CFO layers with a magnetization resulting as expected from the Co2+ ions alone, important changes occur at the interface with BTO over a thickness of 2-3 nm because of the formation of Fe2+ and Co3+ ions. This oxidoreduction process at the interface has strong implications concerning the mechanisms of polarity compensation and coupling in multiferroic heterostructures.
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Affiliation(s)
- Nathalie Jedrecy
- Institut des Nano Sciences de Paris (INSP) , Sorbonne Université, CNRS UMR 7588 , 4 Place Jussieu , 75252 Paris Cedex 05 , France
| | - Thomas Aghavnian
- Service de Physique de l'Etat Condensé (SPEC), CEA, CNRS UMR 3680, Université Paris Saclay, Orme des Merisiers, CEA Saclay , 91191 Gif sur Yvette Cedex , France
| | - Jean-Baptiste Moussy
- Service de Physique de l'Etat Condensé (SPEC), CEA, CNRS UMR 3680, Université Paris Saclay, Orme des Merisiers, CEA Saclay , 91191 Gif sur Yvette Cedex , France
| | - Hélène Magnan
- Service de Physique de l'Etat Condensé (SPEC), CEA, CNRS UMR 3680, Université Paris Saclay, Orme des Merisiers, CEA Saclay , 91191 Gif sur Yvette Cedex , France
| | - Dana Stanescu
- Service de Physique de l'Etat Condensé (SPEC), CEA, CNRS UMR 3680, Université Paris Saclay, Orme des Merisiers, CEA Saclay , 91191 Gif sur Yvette Cedex , France
| | - Xavier Portier
- Centre de recherche sur les Ions, les MAtériaux et la Photonique (CIMAP), CEA, CNRS UMR 6252, ENSICAEN, Normandie Université , 6 Boulevard Maréchal Juin , 14050 Caen , France
| | - Marie-Anne Arrio
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Sorbonne Université, CNRS UMR 7590, IRD, MNHN , 4 Place Jussieu , 75252 Paris Cedex 05 , France
| | - Cristian Mocuta
- Synchrotron SOLEIL, L'Orme des Merisiers Saint-Aubin , BP 48, 91192 Gif sur Yvette Cedex , France
| | - Alina Vlad
- Synchrotron SOLEIL, L'Orme des Merisiers Saint-Aubin , BP 48, 91192 Gif sur Yvette Cedex , France
| | - Rachid Belkhou
- Synchrotron SOLEIL, L'Orme des Merisiers Saint-Aubin , BP 48, 91192 Gif sur Yvette Cedex , France
| | - Philippe Ohresser
- Synchrotron SOLEIL, L'Orme des Merisiers Saint-Aubin , BP 48, 91192 Gif sur Yvette Cedex , France
| | - Antoine Barbier
- Service de Physique de l'Etat Condensé (SPEC), CEA, CNRS UMR 3680, Université Paris Saclay, Orme des Merisiers, CEA Saclay , 91191 Gif sur Yvette Cedex , France
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Rakshit R, Kadakuntla SK, Agarwal P, Sardar S, Saha P, Mandal K, Rana DS. Surface Electronic States Induced High Terahertz Conductivity of Co 3O 4 Microhollow Structure. ACS APPLIED MATERIALS & INTERFACES 2018; 10:19189-19196. [PMID: 29749226 DOI: 10.1021/acsami.8b02925] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Herein, we report the observation of unusual electronic and magnetic phases in traditional antiferromagnetic Co3O4 micromaterials and modulation of their properties on a temperature scale. In particular, we demonstrate a comparative low-energy carrier dynamics of Co3O4 microflower and microhollow flower (MHF) structures of same average size of 2 μm to unravel the ground-state information induced by surface electronics across the insulator-semiconductor transition using terahertz (THz) time domain spectroscopy. Interestingly, the THz optical constants of these structures are found to exhibit remarkably distinct features both as a function of frequency and temperature. Detailed study reveals that the partial metallization through large two-dimensional surface electronic states of MHF structure enables to achieve significantly higher carrier dynamics in contrast to its wide-band-gap solid counterparts and the magnetic measurements reconfirm the presence of these surface states by indicating ferromagnetism in Co3O4 MHF structures. Moreover, the simultaneous existence of insulator-semiconductor and antiferromagnetic-paramagnetic transitions near the Néel temperature points out the significant role of magnetically active Co2+ ions at the tetrahedral site of Co3O4 normal spinel structure in determining the conduction dynamics instead of 3d band related to Co3+ ions at octahedral site. Finally, we demonstrate that the continuous modulation of temperature-controlled charge transport coupled with intrinsic phase transition in Co3O4 microstructures has the potential to design efficient analog-like THz modulator, filter, and sensor. We believe that these outcomes can stimulate new opportunities toward next-generation caloritronics-based ultrafast energy-efficient transition-metal oxide electronics having both economic and environmental significance.
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Affiliation(s)
- Rupali Rakshit
- Department of Physics , Indian Institute of Science Education & Research , Bhopal Bypass Road , Bhauri, Bhopal 462066 , India
- Department of Condensed Matter Physics & Material Sciences , S. N. Bose National Centre for Basic Sciences , Block JD, Sector III , Salt Lake, Kolkata 700106 , India
- Nanoscience & Nanotechnology Center, The Institute of Scientific & Industrial Research , Osaka University , Mihogaoka 8-1 , Ibaraki Osaka 5650871 , Japan
| | - Santhosh Kumar Kadakuntla
- Department of Physics , Indian Institute of Science Education & Research , Bhopal Bypass Road , Bhauri, Bhopal 462066 , India
| | - Piyush Agarwal
- Department of Physics , Indian Institute of Science Education & Research , Bhopal Bypass Road , Bhauri, Bhopal 462066 , India
| | - Suman Sardar
- Department of Physics , Indian Institute of Science Education & Research , Bhopal Bypass Road , Bhauri, Bhopal 462066 , India
| | - Priyanka Saha
- Department of Condensed Matter Physics & Material Sciences , S. N. Bose National Centre for Basic Sciences , Block JD, Sector III , Salt Lake, Kolkata 700106 , India
| | - Kalyan Mandal
- Department of Condensed Matter Physics & Material Sciences , S. N. Bose National Centre for Basic Sciences , Block JD, Sector III , Salt Lake, Kolkata 700106 , India
| | - Dhanvir Singh Rana
- Department of Physics , Indian Institute of Science Education & Research , Bhopal Bypass Road , Bhauri, Bhopal 462066 , India
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Holinsworth BS, Harms NC, Fan S, Mazumdar D, Gupta A, McGill SA, Musfeldt JL. Magnetic field control of charge excitations in CoFe 2O 4. APL MATERIALS 2018; 6:066110. [PMID: 32551187 PMCID: PMC7187867 DOI: 10.1063/1.5021792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 05/03/2018] [Indexed: 06/11/2023]
Abstract
We combine magnetic circular dichroism and photoconductivity with prior optical absorption and first principles calculations to unravel spin-charge interactions in the high Curie temperature magnet CoFe2O4. In addition to revising the bandgap hierarchy, we reveal a broad set of charge transfer excitations in the spin down channel which are sensitive to the metamagnetic transition involving the spin state on Co centers. We also show photoconductivity that depends on an applied magnetic field. These findings open the door for the creation and control of spin-polarized electronic excitations from the minority channel charge transfer in spinel ferrites and other earth-abundant materials.
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Affiliation(s)
- Brian S Holinsworth
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Nathan C Harms
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Shiyu Fan
- Department of Physics, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Dipanjan Mazumdar
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Arun Gupta
- Center for Materials for Information Technology, University of Alabama, Tuscaloosa, Alabama 35487, USA
| | - Stephen A McGill
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA
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Scheiderer P, Schmitt M, Gabel J, Zapf M, Stübinger M, Schütz P, Dudy L, Schlueter C, Lee TL, Sing M, Claessen R. Tailoring Materials for Mottronics: Excess Oxygen Doping of a Prototypical Mott Insulator. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1706708. [PMID: 29732633 DOI: 10.1002/adma.201706708] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 02/02/2018] [Indexed: 06/08/2023]
Abstract
The Mott transistor is a paradigm for a new class of electronic devices-often referred to by the term Mottronics-which are based on charge correlations between the electrons. Since correlation-induced insulating phases of most oxide compounds are usually very robust, new methods have to be developed to push such materials right to the boundary to the metallic phase in order to enable the metal-insulator transition to be switched by electric gating. Here, it is demonstrated that thin films of the prototypical Mott insulator LaTiO3 grown by pulsed laser deposition under oxygen atmosphere are readily tuned by excess oxygen doping across the line of the band-filling controlled Mott transition in the electronic phase diagram. The detected insulator to metal transition is characterized by a strong change in resistivity of several orders of magnitude. The use of suitable substrates and capping layers to inhibit oxygen diffusion facilitates full control of the oxygen content and renders the films stable against exposure to ambient conditions. These achievements represent a significant advancement in control and tuning of the electronic properties of LaTiO3+x thin films making it a promising channel material in future Mottronic devices.
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Affiliation(s)
- Philipp Scheiderer
- Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Würzburg, Am Hubland, D-97074, Würzburg, Germany
| | - Matthias Schmitt
- Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Würzburg, Am Hubland, D-97074, Würzburg, Germany
| | - Judith Gabel
- Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Würzburg, Am Hubland, D-97074, Würzburg, Germany
| | - Michael Zapf
- Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Würzburg, Am Hubland, D-97074, Würzburg, Germany
| | - Martin Stübinger
- Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Würzburg, Am Hubland, D-97074, Würzburg, Germany
| | - Philipp Schütz
- Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Würzburg, Am Hubland, D-97074, Würzburg, Germany
| | - Lenart Dudy
- Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Würzburg, Am Hubland, D-97074, Würzburg, Germany
| | | | - Tien-Lin Lee
- Diamond Light Source Ltd., Didcot, Oxfordshire, OX11 0DE, UK
| | - Michael Sing
- Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Würzburg, Am Hubland, D-97074, Würzburg, Germany
| | - Ralph Claessen
- Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Würzburg, Am Hubland, D-97074, Würzburg, Germany
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Xia W, Wu H, Xue P, Zhu X. Microstructural, Magnetic, and Optical Properties of Pr-Doped Perovskite Manganite La 0.67Ca 0.33MnO 3 Nanoparticles Synthesized via Sol-Gel Process. NANOSCALE RESEARCH LETTERS 2018; 13:135. [PMID: 29728926 PMCID: PMC5935607 DOI: 10.1186/s11671-018-2553-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 04/25/2018] [Indexed: 05/26/2023]
Abstract
We report on microstructural, magnetic, and optical properties of Pr-doped perovskite manganite (La1 - xPrx)0.67Ca0.33MnO3 (LPCMO, x = 0.0-0.5) nanoparticles synthesized via sol-gel process. Structural characterizations (X-ray and electron diffraction patterns, (high resolution) TEM images) provide information regarding the phase formation and the single-crystalline nature of the LPCMO systems. X-ray and electron diffraction patterns reveal that all the LPCMO samples crystallize in perovskite crystallography with an orthorhombic structure (Pnma space group), where the MnO6 octahedron is elongated along the b axis due to the Jahn-Teller effect. That is confirmed by Raman spectra. Crystallite sizes and grain sizes were calculated from XRD and TEM respectively, and the lattice fringes resolved in the high-resolution TEM images of individual LPCMO nanoparticle confirmed its single-crystalline nature. FTIR spectra identify the characteristic Mn-O bond stretching vibration mode near 600 cm- 1, which shifts towards high wavenumbers with increasing post-annealing temperature or Pr-doping concentration, resulting in further distortion of the MnO6 octahedron. XPS revealed dual oxidation states of Mn3+ and Mn4+ in the LPCMO nanoparticles. UV-vis absorption spectra confirm the semiconducting nature of the LPCMO nanoparticles with optical bandgaps of 2.55-2.71 eV. Magnetic measurements as a function of temperature and magnetic field at field cooling and zero-field cooling modes, provided a Curie temperature around 230 K, saturation magnetization of about 81 emu/g, and coercive field of 390 Oe at 10 K. Such magnetic properties and the semiconducting nature of the LPCMO nanoparticles will make them as suitable candidate for magnetic semiconductor spintronics.
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Affiliation(s)
- Weiren Xia
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing, 210093 China
| | - Heng Wu
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing, 210093 China
| | - Piaojie Xue
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing, 210093 China
| | - Xinhua Zhu
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing, 210093 China
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Mihailescu CN, Symeou E, Svoukis E, Negrea RF, Ghica C, Teodorescu V, Tanase LC, Negrila C, Giapintzakis J. Ambiguous Role of Growth-Induced Defects on the Semiconductor-to-Metal Characteristics in Epitaxial VO 2/TiO 2 Thin Films. ACS APPLIED MATERIALS & INTERFACES 2018; 10:14132-14144. [PMID: 29595950 DOI: 10.1021/acsami.8b01436] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Controlling the semiconductor-to-metal transition temperature in epitaxial VO2 thin films remains an unresolved question both at the fundamental as well as the application level. Within the scope of this work, the effects of growth temperature on the structure, chemical composition, interface coherency and electrical characteristics of rutile VO2 epitaxial thin films grown on TiO2 substrates are investigated. It is hereby deduced that the transition temperature is lower than the bulk value of 340 K. However, it is found to approach this value as a function of increased growth temperature even though it is accompanied by a contraction along the V4+-V4+ bond direction, the crystallographic c-axis lattice parameter. Additionally, it is demonstrated that films grown at low substrate temperatures exhibit a relaxed state and a strongly reduced transition temperature. It is suggested that, besides thermal and epitaxial strain, growth-induced defects may strongly affect the electronic phase transition. The results of this work reveal the difficulty in extracting the intrinsic material response to strain, when the exact contribution of all strain sources cannot be effectively determined. The findings also bear implications on the limitations in obtaining the recently predicted novel semi-Dirac point phase in VO2/TiO2 multilayer structures.
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Affiliation(s)
- Cristian N Mihailescu
- Department of Mechanical and Manufacturing Engineering , University of Cyprus , 75 Kallipoleos Avenue , PO Box 20537, 1678 Nicosia , Cyprus
- National Institute for Laser , Plasma and Radiation Physics , 409 Atomistilor Street , PO Box MG-36, 077125 Magurele , Romania
| | - Elli Symeou
- Department of Mechanical and Manufacturing Engineering , University of Cyprus , 75 Kallipoleos Avenue , PO Box 20537, 1678 Nicosia , Cyprus
| | - Efthymios Svoukis
- Department of Mechanical and Manufacturing Engineering , University of Cyprus , 75 Kallipoleos Avenue , PO Box 20537, 1678 Nicosia , Cyprus
| | - Raluca F Negrea
- National Institute of Materials Physics , RO-077125 Magurele , Romania
| | - Corneliu Ghica
- National Institute of Materials Physics , RO-077125 Magurele , Romania
| | | | - Liviu C Tanase
- National Institute of Materials Physics , RO-077125 Magurele , Romania
| | - Catalin Negrila
- National Institute of Materials Physics , RO-077125 Magurele , Romania
| | - John Giapintzakis
- Department of Mechanical and Manufacturing Engineering , University of Cyprus , 75 Kallipoleos Avenue , PO Box 20537, 1678 Nicosia , Cyprus
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Temperature dependence of long coherence times of oxide charge qubits. Sci Rep 2018; 8:3487. [PMID: 29472609 PMCID: PMC5823872 DOI: 10.1038/s41598-018-21767-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 02/09/2018] [Indexed: 12/02/2022] Open
Abstract
The ability to maintain coherence and control in a qubit is a major requirement for quantum computation. We show theoretically that long coherence times can be achieved at easily accessible temperatures (such as boiling point of liquid helium) in small (i.e., ~10 nanometers) charge qubits of oxide double quantum dots when only optical phonons are the source of decoherence. In the regime of strong electron-phonon coupling and in the non-adiabatic region, we employ a duality transformation to make the problem tractable and analyze the dynamics through a non-Markovian quantum master equation. We find that the system decoheres after a long time, despite the fact that no energy is exchanged with the bath. Detuning the dots to a fraction of the optical phonon energy, increasing the electron-phonon coupling, reducing the adiabaticity, or decreasing the temperature enhances the coherence time.
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Joos M, Cerretti G, Veremchuk I, Hofmann P, Frerichs H, Anjum DH, Reich T, Lieberwirth I, Panthöfer M, Zeier WG, Tremel W. Spark Plasma Sintering (SPS)-Assisted Synthesis and Thermoelectric Characterization of Magnéli Phase V 6O 11. Inorg Chem 2018; 57:1259-1268. [PMID: 29323485 DOI: 10.1021/acs.inorgchem.7b02669] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The Magnéli phase V6O11 was synthesized in gram amounts from a powder mixture of V6O11/V7O13 and vanadium metal, using the spark plasma sintering (SPS) technique. Its structure was determined with synchrotron X-ray powder diffraction data from a phase-pure sample synthesized by conventional solid-state synthesis. A special feature of Magnéli-type oxides is a combination of crystallographic shear and intrinsic disorder that leads to relatively low lattice thermal conductivities. SPS prepared V6O11 has a relatively low thermal conductivity of κ = 2.72 ± 0.06 W (m K)-1 while being a n-type conductor with an electrical conductivity of σ = 0.039 ± 0.005 (μΩ m)-1, a Seebeck coefficient of α = -(35 ± 2) μV K-1, which leads to a power factor of PF = 4.9 ± 0.8 × 10-5W (m K2)-1 at ∼600 K. Advances in the application of Magnéli phases are mostly hindered by synthetic and processing challenges, especially when metastable and nanostructured materials such as V6O11 are involved. This study gives insight into the complications of SPS-assisted synthesis of complex oxide materials, provides new information about the thermal and electrical properties of vanadium oxides at high temperatures, and supports the concept of reducing the thermal conductivity of materials with structural building blocks such as crystallographic shear (CS) planes.
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Affiliation(s)
- Markus Joos
- Institut für Anorganische Chemie und Analytische Chemie, Johannes Gutenberg-Universität , Duesbergweg 10-14, D-55099 Mainz, Germany
| | - Giacomo Cerretti
- Institut für Anorganische Chemie und Analytische Chemie, Johannes Gutenberg-Universität , Duesbergweg 10-14, D-55099 Mainz, Germany
| | - Igor Veremchuk
- Max Planck Institute for Chemical Physics of Solids , Nöthnitzer Str. 40, D-01187 Dresden, Germany
| | - Patrick Hofmann
- Physikalisch-Chemisches Institut, Justus-Liebig-Universität Gießen , Heinrich-Buff-Ring-17, 35392 Gießen, Germany
| | - Hajo Frerichs
- Institut für Anorganische Chemie und Analytische Chemie, Johannes Gutenberg-Universität , Duesbergweg 10-14, D-55099 Mainz, Germany
| | - Dalaver H Anjum
- Imaging and Characterization Core Lab, King Abdullah University of Science and Technology , Thuwal 23955-6900, Saudi Arabia
| | - Tobias Reich
- Institut für Kernchemie, Johannes Gutenberg-Universität , Fritz-Straßmann-Weg 2, 55128 Mainz, Germany
| | - Ingo Lieberwirth
- Max Planck Institute for Polymer Research , Ackermannweg 10, D-55128 Mainz, Germany
| | - Martin Panthöfer
- Institut für Anorganische Chemie und Analytische Chemie, Johannes Gutenberg-Universität , Duesbergweg 10-14, D-55099 Mainz, Germany
| | - Wolfgang G Zeier
- Physikalisch-Chemisches Institut, Justus-Liebig-Universität Gießen , Heinrich-Buff-Ring-17, 35392 Gießen, Germany
| | - Wolfgang Tremel
- Institut für Anorganische Chemie und Analytische Chemie, Johannes Gutenberg-Universität , Duesbergweg 10-14, D-55099 Mainz, Germany
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Choi DJ, Robles R, Yan S, Burgess JAJ, Rolf-Pissarczyk S, Gauyacq JP, Lorente N, Ternes M, Loth S. Building Complex Kondo Impurities by Manipulating Entangled Spin Chains. NANO LETTERS 2017; 17:6203-6209. [PMID: 28872317 DOI: 10.1021/acs.nanolett.7b02882] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The creation of molecule-like structures in which magnetic atoms interact controllably is full of potential for the study of complex or strongly correlated systems. Here, we create spin chains in which a strongly correlated Kondo state emerges from magnetic coupling of transition-metal atoms. We build chains up to ten atoms in length by placing Fe and Mn atoms on a Cu2N surface with a scanning tunneling microscope. The atoms couple antiferromagnetically via superexchange interaction through the nitrogen atom network of the surface. The emergent Kondo resonance is spatially distributed along the chain. Its strength can be controlled by mixing atoms of different transition metal elements and manipulating their spatial distribution. We show that the Kondo screening of the full chain by the electrons of the nonmagnetic substrate depends on the interatomic entanglement of the spins in the chain, demonstrating the prerequisites to build and probe spatially extended strongly correlated nanostructures.
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Affiliation(s)
- Deung-Jang Choi
- Max Planck Institute for the Structure and Dynamics of Matter , Luruper Chaussee 149, 22761 Hamburg, Germany
- Max Planck Institute for Solid State Research , Heisenbergstr. 1, 70569 Stuttgart, Germany
| | - Roberto Robles
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology , Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Shichao Yan
- Max Planck Institute for the Structure and Dynamics of Matter , Luruper Chaussee 149, 22761 Hamburg, Germany
- Max Planck Institute for Solid State Research , Heisenbergstr. 1, 70569 Stuttgart, Germany
| | - Jacob A J Burgess
- Max Planck Institute for the Structure and Dynamics of Matter , Luruper Chaussee 149, 22761 Hamburg, Germany
- Max Planck Institute for Solid State Research , Heisenbergstr. 1, 70569 Stuttgart, Germany
| | - Steffen Rolf-Pissarczyk
- Max Planck Institute for the Structure and Dynamics of Matter , Luruper Chaussee 149, 22761 Hamburg, Germany
- Max Planck Institute for Solid State Research , Heisenbergstr. 1, 70569 Stuttgart, Germany
| | - Jean-Pierre Gauyacq
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Univ. Paris-Sud, Université Paris-Saclay , Bât. 351, 91405 Orsay Cedex, France
| | - Nicolás Lorente
- Centro de Física de Materiales, CFM/MPC (CSIC-UPV/EHU) , Paseo Manuel de Lardizabal 5, 20018 Donostia-San Sebastián, Spain
- Donostia International Physics Center (DIPC) , Paseo Manuel de Lardizabal 4, 20018 Donostia-San Sebastián, Spain
| | - Markus Ternes
- Max Planck Institute for Solid State Research , Heisenbergstr. 1, 70569 Stuttgart, Germany
| | - Sebastian Loth
- Max Planck Institute for the Structure and Dynamics of Matter , Luruper Chaussee 149, 22761 Hamburg, Germany
- Max Planck Institute for Solid State Research , Heisenbergstr. 1, 70569 Stuttgart, Germany
- Institute for Functional Matter and Quantum Technologies, University of Stuttgart , Pfaffenwaldring 57, 70569 Stuttgart, Germany
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34
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Interface-induced multiferroism by design in complex oxide superlattices. Proc Natl Acad Sci U S A 2017; 114:E5062-E5069. [PMID: 28607082 DOI: 10.1073/pnas.1706814114] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Interfaces between materials present unique opportunities for the discovery of intriguing quantum phenomena. Here, we explore the possibility that, in the case of superlattices, if one of the layers is made ultrathin, unexpected properties can be induced between the two bracketing interfaces. We pursue this objective by combining advanced growth and characterization techniques with theoretical calculations. Using prototype La2/3Sr1/3MnO3 (LSMO)/BaTiO3 (BTO) superlattices, we observe a structural evolution in the LSMO layers as a function of thickness. Atomic-resolution EM and spectroscopy reveal an unusual polar structure phase in ultrathin LSMO at a critical thickness caused by interfacing with the adjacent BTO layers, which is confirmed by first principles calculations. Most important is the fact that this polar phase is accompanied by reemergent ferromagnetism, making this system a potential candidate for ultrathin ferroelectrics with ferromagnetic ordering. Monte Carlo simulations illustrate the important role of spin-lattice coupling in LSMO. These results open up a conceptually intriguing recipe for developing functional ultrathin materials via interface-induced spin-lattice coupling.
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35
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Fujita A, Kinemuchi Y, Yamaguchi W. Study of entropic characteristics of strongly correlated systems using VO 2 as a model case. Phys Chem Chem Phys 2016; 18:30824-30829. [PMID: 27801443 DOI: 10.1039/c6cp06200h] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
To explain the huge caloric effects often observed in the first-order electronic phase transition in the strongly correlated oxides, the entropic characteristics are investigated in VO2. By evaluating the spin and charge fluctuations based on the local moment model and the Sommerfeld coefficient in the high-temperature rutile phase, it is found that these fluctuations of the high-temperature phase are the main source of the entropic change during the transition. This mode of entropic change is realized by the quenching of these fluctuations owing to the formation of a singlet bonding state in the low-temperature monoclinic phase. By introducing oxygen deficiency, a vagueness in the gap at the Fermi level is confirmed by the transport data, the X-ray photoelectron spectra and also the electronic structure calculated by the first-principles calculations. In this case, the entropic feature at the transition is weakened. Consequently, the large caloric phenomena of the strongly correlated oxides are a result of the conversion of the internal energy gain owing to the orbital selection at the ground state into the free energy gain owing to the spin and charge fluctuations at finite temperature.
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Affiliation(s)
- Asaya Fujita
- Magnetic Powder Metallurgy Research Center, AIST Chubu, 2266-98 Anagahora, Shimo-Shidami, Moriyama-ku, Nagoya 463-8560, Japan.
| | - Yoshiaki Kinemuchi
- Magnetic Powder Metallurgy Research Center, AIST Chubu, 2266-98 Anagahora, Shimo-Shidami, Moriyama-ku, Nagoya 463-8560, Japan.
| | - Wataru Yamaguchi
- Magnetic Powder Metallurgy Research Center, AIST Chubu, 2266-98 Anagahora, Shimo-Shidami, Moriyama-ku, Nagoya 463-8560, Japan.
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36
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Liu HJ, Lin JC, Fang YW, Wang JC, Huang BC, Gao X, Huang R, Dean PR, Hatton PD, Chin YY, Lin HJ, Chen CT, Ikuhara Y, Chiu YP, Chang CS, Duan CG, He Q, Chu YH. A Metal-Insulator Transition of the Buried MnO 2 Monolayer in Complex Oxide Heterostructure. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2016; 28:9142-9151. [PMID: 27571277 DOI: 10.1002/adma.201602281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 07/10/2016] [Indexed: 06/06/2023]
Abstract
A novel artificially created MnO2 monolayer system is demonstrated in atomically controlled epitaxial perovskite heterostructures. With careful design of different electrostatic boundary conditions, a magnetic transition as well as a metal-insulator transition of the MnO2 monolayer is unveiled, providing a fundamental understanding of dimensionality-confined strongly correlated electron systems and a direction to design new electronic devices.
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Affiliation(s)
- Heng-Jui Liu
- Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu, 30010, Taiwan
- Department of Physics, National Taiwan Normal University, Taipei, 11677, Taiwan
| | - Jheng-Cyuan Lin
- Institute of Physics, Academia Sinica, Taipei, 11529, Taiwan
| | - Yue-Wen Fang
- Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai, 200241, China
| | - Jing-Ching Wang
- Department of Physics, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan
| | - Bo-Chao Huang
- Institute of Physics, Academia Sinica, Taipei, 11529, Taiwan
| | - Xiang Gao
- Nanostructures Research Laboratory, Japan Fine Ceramics Center, Nagoya, 456-8587, Japan
| | - Rong Huang
- Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai, 200241, China
- Nanostructures Research Laboratory, Japan Fine Ceramics Center, Nagoya, 456-8587, Japan
| | - Philip R Dean
- Department of Physics, Durham University, Durham DH1 3LE, UK
| | - Peter D Hatton
- Department of Physics, Durham University, Durham DH1 3LE, UK
| | - Yi-Ying Chin
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
| | - Hong-Ji Lin
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
| | - Chien-Te Chen
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
| | - Yuichi Ikuhara
- Nanostructures Research Laboratory, Japan Fine Ceramics Center, Nagoya, 456-8587, Japan
- Institute of Engineering Innovation, The University of Tokyo, Tokyo, 113-8656, Japan
| | - Ya-Ping Chiu
- Department of Physics, National Taiwan Normal University, Taipei, 11677, Taiwan
- Department of Physics, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan
| | - Chia-Seng Chang
- Institute of Physics, Academia Sinica, Taipei, 11529, Taiwan
| | - Chun-Gang Duan
- Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai, 200241, China
| | - Qing He
- Department of Physics, Durham University, Durham DH1 3LE, UK.
| | - Ying-Hao Chu
- Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu, 30010, Taiwan.
- Institute of Physics, Academia Sinica, Taipei, 11529, Taiwan.
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37
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Mazza G, Amaricci A, Capone M, Fabrizio M. Field-Driven Mott Gap Collapse and Resistive Switch in Correlated Insulators. PHYSICAL REVIEW LETTERS 2016; 117:176401. [PMID: 27824473 PMCID: PMC5423525 DOI: 10.1103/physrevlett.117.176401] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Indexed: 05/07/2023]
Abstract
Mott insulators are "unsuccessful metals" in which Coulomb repulsion prevents charge conduction despite a metal-like concentration of conduction electrons. The possibility to unlock the frozen carriers with an electric field offers tantalizing prospects of realizing new Mott-based microelectronic devices. Here we unveil how such unlocking happens in a simple model that shows the coexistence of a stable Mott insulator and a metastable metal. Considering a slab subject to a linear potential drop, we find, by means of the dynamical mean-field theory, that the electric breakdown of the Mott insulator occurs via a first-order insulator-to-metal transition characterized by an abrupt gap collapse in sharp contrast to the standard Zener breakdown. The switch on of conduction is due to the field-driven stabilization of the metastable metallic phase. Outside the region of insulator-metal coexistence, the electric breakdown occurs through a more conventional quantum tunneling across the Hubbard bands tilted by the field. Our findings rationalize recent experimental observations and may offer a guideline for future technological research.
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Affiliation(s)
- G Mazza
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), Via Bonomea 265, 34136 Trieste, Italy
- Centre de Physique Théorique, École Polytechnique, CNRS, Université Paris-Saclay, 91128 Palaiseau, France
- Collège de France, 11 place Marcelin Berthelot, 75005 Paris, France
| | - A Amaricci
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), and Democritos National Simulation Center, Consiglio Nazionale delle Ricerche, Istituto Officina dei Materiali (CNR-IOM), Via Bonomea 265, 34136 Trieste, Italy
| | - M Capone
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), Via Bonomea 265, 34136 Trieste, Italy
| | - M Fabrizio
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), Via Bonomea 265, 34136 Trieste, Italy
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38
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Mannhart J, Boschker H, Kopp T, Valentí R. Artificial atoms based on correlated materials. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2016; 79:084508. [PMID: 27427430 DOI: 10.1088/0034-4885/79/8/084508] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Low-dimensional electron systems fabricated from quantum matter have in recent years become available and are being explored with great intensity. This article gives an overview of the fundamental properties of such systems and summarizes the state of the field. We furthermore present and consider the concept of artificial atoms fabricated from quantum materials, anticipating remarkable scientific advances and possibly important applications of this new field of research. The surprising properties of these artificial atoms and of molecules or even of solids assembled from them are presented and discussed.
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Affiliation(s)
- J Mannhart
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
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39
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Booth JM, Drumm DW, Casey PS, Smith JS, Russo SP. Hubbard physics in the PAW GW approximation. J Chem Phys 2016; 144:244110. [DOI: 10.1063/1.4954508] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- J. M. Booth
- Theoretical Chemical and Quantum Physics, School of Science, RMIT University, Melbourne, VIC, Australia
| | - D. W. Drumm
- Theoretical Chemical and Quantum Physics, School of Science, RMIT University, Melbourne, VIC, Australia
- Australian Research Council Centre of Excellence for Nanoscale BioPhotonics, School of Science, RMIT University, Melbourne, VIC, Australia
| | - P. S. Casey
- CSIRO Manufacturing, Clayton, VIC, Australia
| | - J. S. Smith
- Theoretical Chemical and Quantum Physics, School of Science, RMIT University, Melbourne, VIC, Australia
| | - S. P. Russo
- Theoretical Chemical and Quantum Physics, School of Science, RMIT University, Melbourne, VIC, Australia
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40
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Di Gioacchino D, Puri A, Marcelli A, Poccia N, Ricci A, Bianconi A. The flux dynamics behavior of the two competing high temperature superconducting phases in underdoped LaCuO4.06. Phys Chem Chem Phys 2016; 18:12534-40. [PMID: 27087671 DOI: 10.1039/c6cp01400c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In complex transition metal oxides (TMO) an arrested electronic phase separation (PS) appears by tuning the system near a Lifshitz transition in multiband Hubbard models. The PS in La2CuO4+y near insulator to metal transition (IMT) is made of short range Charge Density Wave (CDW) order inhomogeneity coexisting with quenched lattice disorder. While at high doping y = 0.1 percolation gives a single superconducting phase, near the IMT at y = 0.06 two coexisting superconducting phases appear: the first one with a critical temperature Tc1 = 16 K and the second one with Tc2 = 29 K. It is known that the two superconducting phases are characterized by two different space geometry because of two different spatial distributions of both CDW order and dopants self-organization. Here we show that these two phases show different flux dynamic regimes using alternating current (AC) multi-harmonic susceptibility experiments. This is a unique technique capable to investigate multi-phase superconductors and characterize their transport properties in a percolative scenario. Results point out that the low critical temperature phase is well described by a bulk-like flux pinning with a 2D geometry while the phase with higher critical temperature shows a 'barrier pinning' mechanism providing direct evidence of two different superconducting vortex dynamics in different complex geometrical spaces.
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Affiliation(s)
- D Di Gioacchino
- Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, 00044 Frascati (RM), Italy.
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41
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Amrillah T, Vandrangi SK, Bitla Y, Do TH, Liao SC, Tsai CY, Chin YY, Liu YT, Lin ML, He Q, Lin HJ, Lee HY, Lai CH, Arenholz E, Juang JY, Chu YH. Tuning the magnetic properties of self-assembled BiFeO3-CoFe2O4 heteroepitaxy by magneto-structural coupling. NANOSCALE 2016; 8:8847-8854. [PMID: 27072287 DOI: 10.1039/c5nr09269h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Magnetic and multiferroic nanocomposites with two distinct phases have been a topic of intense research for their profound potential applications in the field of spintronics. In addition to growing high-quality phase separated heteroepitaxial nanocomposites, the strain engineering that is conducive to enhance the tunability of material properties, in general, and the magnetic properties, in particular, is of utmost importance in exploring new possibilities. Here, we investigated the magneto-structural coupling between antiferromagnetic BiFeO3 (BFO) and ferrimagnetic CoFe2O4 (CFO) in self-assembled vertically aligned nanocomposites grown on LaAlO3 (LAO) and SrTiO3 (STO) substrates. We found that BFO exhibits tetragonal (T) and rhombohedral (R) structures as the stable phases and CFO has high magnetocrystalline anisotropy even in the form of nanocomposites. The temperature and magnetic field dependent magnetizations of T_BFO-CFO/LAO and R_BFO-CFO/STO nanocomposites primarily demonstrate the magnetoelastic coupling between these variants.
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Affiliation(s)
- Tahta Amrillah
- Department of Electrophysics, National Chiao Tung University, Hsinchu 30010, Taiwan.
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42
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Moon SY, Moon CW, Chang HJ, Kim T, Kang CY, Choi HJ, Kim JS, Baek SH, Jang HW. Thermal stability of 2DEG at amorphous LaAlO 3/crystalline SrTiO 3 heterointerfaces. NANO CONVERGENCE 2016; 3:7. [PMID: 28191417 PMCID: PMC5271142 DOI: 10.1186/s40580-016-0067-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 02/10/2016] [Indexed: 06/06/2023]
Abstract
At present, the generation of heterostructures with two dimensional electron gas (2DEG) in amorphous LaAlO3 (a-LAO)/SrTiO3 (STO) has been achieved. Herein, we analysed thermal stability of 2DEG at a-LAO/STO interfaces in comparison with 2DEG at crystalline LaAlO3 (c-LAO)/STO interfaces. To create 2DEG at LAO/STO interface, regardless of growing temperature from 25 to 700 °C, we found that environment with oxygen deficient during the deposition of LAO overlayer is essentially required. That indicates that the oxygen-poor condition in the system is more essential than the crystalline nature of LAO layer. 2DEG at a-LAO/STO interface is depleted upon ex situ annealing at 300 °C under 300 Torr of oxygen pressure, while that in c-LAO/STO interface is still maintained. Our result suggests that the LAO overlayer crystallinity critically affects the thermal-annealing-induced depletion of 2DEG at a-LAO/STO interface rather than the generation of 2DEG. We clearly provide that amorphous TiOx can efficiently prevent the thermal degradation of 2DEG at the a-LAO/STO interface, which gives a cornerstone for achieving thermal-stable 2DEG at a-LAO/STO interface.
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Affiliation(s)
- Seon Young Moon
- Center for Electronic Materials, Korea Institute of Science and Technology, Seoul, 136-791 Republic of Korea
- Department of Materials Science and Engineering, Yonsei University, Seoul, 120-749 Republic of Korea
| | - Cheon Woo Moon
- Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Seoul, 151-744 Republic of Korea
| | - Hye Jung Chang
- Center for Electronic Materials, Korea Institute of Science and Technology, Seoul, 136-791 Republic of Korea
- Department of Nanomaterials Science and Technology, Korea University of Science and Technology, Daejeon, 305-350 Republic of Korea
| | - Taemin Kim
- Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Seoul, 151-744 Republic of Korea
| | - Chong-Yun Kang
- Center for Electronic Materials, Korea Institute of Science and Technology, Seoul, 136-791 Republic of Korea
- Department of Nanomaterials Science and Technology, Korea University of Science and Technology, Daejeon, 305-350 Republic of Korea
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 136-701 Republic of Korea
| | - Heon-Jin Choi
- Department of Materials Science and Engineering, Yonsei University, Seoul, 120-749 Republic of Korea
| | - Jin-Sang Kim
- Center for Electronic Materials, Korea Institute of Science and Technology, Seoul, 136-791 Republic of Korea
| | - Seung-Hyub Baek
- Center for Electronic Materials, Korea Institute of Science and Technology, Seoul, 136-791 Republic of Korea
- Department of Nanomaterials Science and Technology, Korea University of Science and Technology, Daejeon, 305-350 Republic of Korea
| | - Ho Won Jang
- Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Seoul, 151-744 Republic of Korea
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43
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Lee SA, Jeong H, Woo S, Hwang JY, Choi SY, Kim SD, Choi M, Roh S, Yu H, Hwang J, Kim SW, Choi WS. Phase transitions via selective elemental vacancy engineering in complex oxide thin films. Sci Rep 2016; 6:23649. [PMID: 27033718 PMCID: PMC4817049 DOI: 10.1038/srep23649] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 03/11/2016] [Indexed: 11/08/2022] Open
Abstract
Defect engineering has brought about a unique level of control for Si-based semiconductors, leading to the optimization of various opto-electronic properties and devices. With regard to perovskite transition metal oxides, O vacancies have been a key ingredient in defect engineering, as they play a central role in determining the crystal field and consequent electronic structure, leading to important electronic and magnetic phase transitions. Therefore, experimental approaches toward understanding the role of defects in complex oxides have been largely limited to controlling O vacancies. In this study, we report on the selective formation of different types of elemental vacancies and their individual roles in determining the atomic and electronic structures of perovskite SrTiO3 (STO) homoepitaxial thin films fabricated by pulsed laser epitaxy. Structural and electronic transitions have been achieved via selective control of the Sr and O vacancy concentrations, respectively, indicating a decoupling between the two phase transitions. In particular, O vacancies were responsible for metal-insulator transitions, but did not influence the Sr vacancy induced cubic-to-tetragonal structural transition in epitaxial STO thin film. The independent control of multiple phase transitions in complex oxides by exploiting selective vacancy engineering opens up an unprecedented opportunity toward understanding and customizing complex oxide thin films.
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Affiliation(s)
- Sang A. Lee
- Department of Physics, Sungkyunkwan University, Suwon, 16419, Korea
- Insitute of Basic Science, Sungkyunkwan University, Suwon, 16419, Korea
| | - Hoidong Jeong
- Department of Physics, Sungkyunkwan University, Suwon, 16419, Korea
| | - Sungmin Woo
- Department of Physics, Sungkyunkwan University, Suwon, 16419, Korea
| | - Jae-Yeol Hwang
- Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS) Sungkyunkwan University, Suwon 16419, Korea
| | - Si-Young Choi
- Materials Modeling and Characterization Department, Korea Institute of Materials Science, Changwon 51508, Korea
| | - Sung-Dae Kim
- Materials Modeling and Characterization Department, Korea Institute of Materials Science, Changwon 51508, Korea
| | - Minseok Choi
- Materials Modeling and Characterization Department, Korea Institute of Materials Science, Changwon 51508, Korea
- Department of Physics, Inha University, Incheon 22212, Korea
| | - Seulki Roh
- Department of Physics, Sungkyunkwan University, Suwon, 16419, Korea
| | - Hosung Yu
- Department of Physics, Inha University, Incheon 22212, Korea
- Department of Energy Sciences, Sungkyunkwan University, Suwon 16419, Korea
| | - Jungseek Hwang
- Department of Physics, Sungkyunkwan University, Suwon, 16419, Korea
| | - Sung Wng Kim
- Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS) Sungkyunkwan University, Suwon 16419, Korea
- Department of Physics, Inha University, Incheon 22212, Korea
- Department of Energy Sciences, Sungkyunkwan University, Suwon 16419, Korea
| | - Woo Seok Choi
- Department of Physics, Sungkyunkwan University, Suwon, 16419, Korea
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44
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Rödel TC, Fortuna F, Sengupta S, Frantzeskakis E, Le Fèvre P, Bertran F, Mercey B, Matzen S, Agnus G, Maroutian T, Lecoeur P, Santander-Syro AF. Universal Fabrication of 2D Electron Systems in Functional Oxides. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2016; 28:1976-1980. [PMID: 26753522 DOI: 10.1002/adma.201505021] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 11/19/2015] [Indexed: 06/05/2023]
Abstract
2D electron systems (2DESs) in functional oxides are promising for applications, but their fabrication and use, essentially limited to SrTiO3 -based heterostructures, are hampered by the need for growing complex oxide overlayers thicker than 2 nm using evolved techniques. It is demonstrated that thermal deposition of a monolayer of an elementary reducing agent suffices to create 2DESs in numerous oxides.
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Affiliation(s)
- Tobias Chris Rödel
- CSNSM, Univ. Paris-Sud, CNRS/IN2P3, Université Paris-Saclay, 91405, Orsay, France
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin-BP48, 91192, Gif-sur-Yvette, France
| | - Franck Fortuna
- CSNSM, Univ. Paris-Sud, CNRS/IN2P3, Université Paris-Saclay, 91405, Orsay, France
| | - Shamashis Sengupta
- Laboratoire de Physique des Solides, Univ. Paris-Sud, CNRS, Université Paris-Saclay, 91405, Orsay, France
| | | | - Patrick Le Fèvre
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin-BP48, 91192, Gif-sur-Yvette, France
| | - François Bertran
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin-BP48, 91192, Gif-sur-Yvette, France
| | - Bernard Mercey
- CRISMAT, ENSICAEN-CNRS UMR6508, 6 bd. Maréchal Juin, 14050, Caen, France
| | - Sylvia Matzen
- Institut d'Electronique Fondamentale, Univ. Paris-Sud, CNRS, Université Paris-Saclay, 91405, Orsay, France
| | - Guillaume Agnus
- Institut d'Electronique Fondamentale, Univ. Paris-Sud, CNRS, Université Paris-Saclay, 91405, Orsay, France
| | - Thomas Maroutian
- Institut d'Electronique Fondamentale, Univ. Paris-Sud, CNRS, Université Paris-Saclay, 91405, Orsay, France
| | - Philippe Lecoeur
- Institut d'Electronique Fondamentale, Univ. Paris-Sud, CNRS, Université Paris-Saclay, 91405, Orsay, France
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45
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Lin JC, Tra VT, Tsai DS, Lin TT, Huang PC, Hsu WL, Wu HJ, Huang R, Van Chien N, Yoshida R, Lin JY, Ikuhara Y, Chiu YP, Gwo S, Tsai DP, He JH, Chu YH. Control of the Metal-Insulator Transition at Complex Oxide Heterointerfaces through Visible Light. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2016; 28:764-770. [PMID: 26607052 DOI: 10.1002/adma.201503499] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2015] [Revised: 10/14/2015] [Indexed: 06/05/2023]
Abstract
The coupling of the localized surface plasmon resonance of Au nanoparticles is utilized to deliver a visible-light stimulus to control conduction at the LaAlO3 /SrTiO3 interface. A giant photoresponse and the controllable metal-insulator transition are characterized at this heterointerface. This study paves a new route to optical control of the functionality at the heterointerfaces.
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Affiliation(s)
- Jheng-Cyuan Lin
- Institute of Physics, Academia Sinica, Taipei, 11529, Taiwan
| | - Vu Thanh Tra
- Institute of Physics, National Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Dung-Sheng Tsai
- Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei, 10617, Taiwan
- Research Center for Applied Sciences, Academia Sinica, Taipei, 11529, Taiwan
| | - Tai-Te Lin
- Department of Physics, National Sun Yat-sen University, Kaohsiung, 804, Taiwan
| | - Po-Cheng Huang
- Department of Physics, National Sun Yat-sen University, Kaohsiung, 804, Taiwan
| | - Wei-Lun Hsu
- Department of Physics, National Taiwan University, Taipei, 10617, Taiwan
| | - Hui Jun Wu
- Department of Physics, National Taiwan University, Taipei, 10617, Taiwan
| | - Rong Huang
- Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai, 200062, China
- Nanostructures Research Laboratory, Japan Fine Ceramics Center, Nagoya, 456-8587, Japan
| | - Nguyen Van Chien
- Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Ryuji Yoshida
- Nanostructures Research Laboratory, Japan Fine Ceramics Center, Nagoya, 456-8587, Japan
| | - Jiunn-Yuan Lin
- Institute of Physics, National Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Yuichi Ikuhara
- Nanostructures Research Laboratory, Japan Fine Ceramics Center, Nagoya, 456-8587, Japan
- Institute of Engineering Innovation, The University of Tokyo, Tokyo, 113-8656, Japan
| | - Ya-Ping Chiu
- Department of Physics, National Sun Yat-sen University, Kaohsiung, 804, Taiwan
- Department of Physics, National Taiwan Normal University, Taipei, 116, Taiwan
| | - Shangjr Gwo
- Department of Physics, National Tsing-Hua University, Hsinchu, 30013, Taiwan
| | - Din Ping Tsai
- Research Center for Applied Sciences, Academia Sinica, Taipei, 11529, Taiwan
- Department of Physics, National Taiwan University, Taipei, 10617, Taiwan
| | - Jr-Hau He
- Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei, 10617, Taiwan
- Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Ying-Hao Chu
- Institute of Physics, Academia Sinica, Taipei, 11529, Taiwan
- Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu, 30010, Taiwan
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46
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Salvinelli G, Drera G, Giampietri A, Sangaletti L. Layer-Resolved Cation Diffusion and Stoichiometry at the LaAlO3/SrTiO3 Heterointerface Probed by X-ray Photoemission Experiments and Site Occupancy Modeling. ACS APPLIED MATERIALS & INTERFACES 2015; 7:25648-25657. [PMID: 26559612 DOI: 10.1021/acsami.5b06094] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The layer-resolved cation occupancy for different conducting and insulating interfaces of LaAlO3 (LAO) thin films on SrTiO3 (STO) has been determined by angle-resoled X-ray photoelectron spectroscopy (AR-XPS). Three STO interfaces with LAO have been considered, namely, a conducting interface with a 5 unit cell (u.c.) LAO layer, an insulating interface with a 5 u.c. LAO layer, and an insulating interface with a 3 u.c. LAO layer. Considering inelastic and elastic scattering processes in the transport approximation, the core-level signal attenuation has been modeled on the basis of Monte Carlo calculations of the electron trajectories across the heterostructures. Different effects involving cation stoichiometry and diffusion through the interface have been considered to interpret data. Beyond a mere abrupt interface modeling, the LaAlO3/SrTiO3 heterojunction is shown to host cation diffusion processes within 3-4 unit cells in the bulk layer, along with a clear Sr substoichiometry, an issue so far virtually neglected in the analysis of these systems. The present results show the capability of the AR-XPS modeling to explore element-sensitive properties at the oxide interfaces, matching and completing the information that can be provided by probes based on electron microscopy or X-ray scattering.
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Affiliation(s)
- Gabriele Salvinelli
- Interdisciplinary Laboratories for Advanced Materials Physics (I-LAMP) and Dipartimento di Matematica e Fisica, Università Cattolica del Sacro Cuore , via dei Musei 41, 25121 Brescia, Italy
| | - Giovanni Drera
- Interdisciplinary Laboratories for Advanced Materials Physics (I-LAMP) and Dipartimento di Matematica e Fisica, Università Cattolica del Sacro Cuore , via dei Musei 41, 25121 Brescia, Italy
| | - Alessio Giampietri
- Interdisciplinary Laboratories for Advanced Materials Physics (I-LAMP) and Dipartimento di Matematica e Fisica, Università Cattolica del Sacro Cuore , via dei Musei 41, 25121 Brescia, Italy
| | - Luigi Sangaletti
- Interdisciplinary Laboratories for Advanced Materials Physics (I-LAMP) and Dipartimento di Matematica e Fisica, Università Cattolica del Sacro Cuore , via dei Musei 41, 25121 Brescia, Italy
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47
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Chen C, Avila J, Frantzeskakis E, Levy A, Asensio MC. Observation of a two-dimensional liquid of Fröhlich polarons at the bare SrTiO3 surface. Nat Commun 2015; 6:8585. [PMID: 26489376 PMCID: PMC4639792 DOI: 10.1038/ncomms9585] [Citation(s) in RCA: 106] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 09/08/2015] [Indexed: 11/24/2022] Open
Abstract
The polaron is a quasi-particle formed by a conduction electron (or hole) together with its self-induced polarization in a polar semiconductor or an ionic crystal. Among various polarizable examples of complex oxides, strontium titanate (SrTiO3) is one of the most studied. Here we examine the carrier type and the interplay of inner degrees of freedom (for example, charge, lattice, orbital) in SrTiO3. We report the experimental observation of Fröhlich polarons, or large polarons, at the bare SrTiO3 surface prepared by vacuum annealing. Systematic analyses of angle-resolved photoemission spectroscopy and X-ray absorption spectra show that these Fröhlich polarons are two-dimensional and only exist with inversion symmetry breaking by two-dimensional oxygen vacancies. Our discovery provides a rare solvable field theoretical model, and suggests the relevance of large (bi)polarons for superconductivity in perovskite oxides, as well as in high-temperature superconductors. A polaron is a quasiparticle formed through the strong interaction between an electron and the ions in a crystalline solid. Here, the authors observe Fröhlich polarons, formed by the coupling of electrons and long-wavelength optical phonons, in strontium titanate.
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Affiliation(s)
- Chaoyu Chen
- Synchrotron SOLEIL, Beamline ANTARES, L'Orme des Merisiers, Saint Aubin-BP 48, Gif surYvette 91192, France
| | - José Avila
- Synchrotron SOLEIL, Beamline ANTARES, L'Orme des Merisiers, Saint Aubin-BP 48, Gif surYvette 91192, France
| | - Emmanouil Frantzeskakis
- Synchrotron SOLEIL, Beamline ANTARES, L'Orme des Merisiers, Saint Aubin-BP 48, Gif surYvette 91192, France
| | - Anna Levy
- Synchrotron SOLEIL, Beamline ANTARES, L'Orme des Merisiers, Saint Aubin-BP 48, Gif surYvette 91192, France
| | - Maria C Asensio
- Synchrotron SOLEIL, Beamline ANTARES, L'Orme des Merisiers, Saint Aubin-BP 48, Gif surYvette 91192, France
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48
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Zhang HT, Zhang L, Mukherjee D, Zheng YX, Haislmaier RC, Alem N, Engel-Herbert R. Wafer-scale growth of VO2 thin films using a combinatorial approach. Nat Commun 2015; 6:8475. [PMID: 26450653 PMCID: PMC4633718 DOI: 10.1038/ncomms9475] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 08/25/2015] [Indexed: 11/09/2022] Open
Abstract
Transition metal oxides offer functional properties beyond conventional semiconductors. Bridging the gap between the fundamental research frontier in oxide electronics and their realization in commercial devices demands a wafer-scale growth approach for high-quality transition metal oxide thin films. Such a method requires excellent control over the transition metal valence state to avoid performance deterioration, which has been proved challenging. Here we present a scalable growth approach that enables a precise valence state control. By creating an oxygen activity gradient across the wafer, a continuous valence state library is established to directly identify the optimal growth condition. Single-crystalline VO2 thin films have been grown on wafer scale, exhibiting more than four orders of magnitude change in resistivity across the metal-to-insulator transition. It is demonstrated that ‘electronic grade' transition metal oxide films can be realized on a large scale using a combinatorial growth approach, which can be extended to other multivalent oxide systems. Precise valence state control to avoid performance deterioration in transition metal oxide films has proved challenging. Here, the authors establish a combinatorial approach to create a valence state library of VO2, allowing for the growth of wafer size VO2 thin films.
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Affiliation(s)
- Hai-Tian Zhang
- Department of Materials Science and Engineering and Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Lei Zhang
- Department of Materials Science and Engineering and Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Debangshu Mukherjee
- Department of Materials Science and Engineering and Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Yuan-Xia Zheng
- Department of Physics, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Ryan C Haislmaier
- Department of Materials Science and Engineering and Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Nasim Alem
- Department of Materials Science and Engineering and Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Roman Engel-Herbert
- Department of Materials Science and Engineering and Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802, USA
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49
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Quackenbush NF, Paik H, Woicik JC, Arena DA, Schlom DG, Piper LFJ. X-Ray Spectroscopy of Ultra-Thin Oxide/Oxide Heteroepitaxial Films: A Case Study of Single-Nanometer VO2/TiO2. MATERIALS 2015; 8:5452-5466. [PMID: 28793516 PMCID: PMC5455529 DOI: 10.3390/ma8085255] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 08/12/2015] [Accepted: 08/14/2015] [Indexed: 11/23/2022]
Abstract
Epitaxial ultra-thin oxide films can support large percent level strains well beyond their bulk counterparts, thereby enabling strain-engineering in oxides that can tailor various phenomena. At these reduced dimensions (typically < 10 nm), contributions from the substrate can dwarf the signal from the epilayer, making it difficult to distinguish the properties of the epilayer from the bulk. This is especially true for oxide on oxide systems. Here, we have employed a combination of hard X-ray photoelectron spectroscopy (HAXPES) and angular soft X-ray absorption spectroscopy (XAS) to study epitaxial VO2/TiO2 (100) films ranging from 7.5 to 1 nm. We observe a low-temperature (300 K) insulating phase with evidence of vanadium-vanadium (V-V) dimers and a high-temperature (400 K) metallic phase absent of V-V dimers irrespective of film thickness. Our results confirm that the metal insulator transition can exist at atomic dimensions and that biaxial strain can still be used to control the temperature of its transition when the interfaces are atomically sharp. More generally, our case study highlights the benefits of using non-destructive XAS and HAXPES to extract out information regarding the interfacial quality of the epilayers and spectroscopic signatures associated with exotic phenomena at these dimensions.
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Affiliation(s)
- Nicholas F Quackenbush
- Department of Physics, Applied Physics and Astronomy, Binghamton University, Binghamton, NY 13902, USA.
| | - Hanjong Paik
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY 14853, USA.
| | - Joseph C Woicik
- Materials Science and Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
| | - Dario A Arena
- National Synchrotron Light Source-II, Brookhaven National Laboratory, Upton, NY 11973, USA.
| | - Darrell G Schlom
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY 14853, USA.
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY 14853, USA.
| | - Louis F J Piper
- Department of Physics, Applied Physics and Astronomy, Binghamton University, Binghamton, NY 13902, USA.
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50
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Kobayashi M, Yoshimatsu K, Sakai E, Kitamura M, Horiba K, Fujimori A, Kumigashira H. Origin of the Anomalous Mass Renormalization in Metallic Quantum Well States of Strongly Correlated Oxide SrVO_{3}. PHYSICAL REVIEW LETTERS 2015; 115:076801. [PMID: 26317738 DOI: 10.1103/physrevlett.115.076801] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Indexed: 06/04/2023]
Abstract
In situ angle-resolved photoemission spectroscopy (ARPES) has been performed on SrVO_{3} ultrathin films, which show metallic quantum well (QW) states, to unveil the origin of the anomalous mass enhancement in the QW subbands. The line-shape analysis of the ARPES spectra reveals that the strength of the electron correlation increases as the subband bottom energy approaches the Fermi level. These results indicate that the anomalous subband-dependent mass enhancement mainly arises from the quasi-one-dimensional character of confined V 3d states as a result of their orbital-selective quantization.
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Affiliation(s)
- Masaki Kobayashi
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba 305-0801, Japan
| | - Kohei Yoshimatsu
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba 305-0801, Japan
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Enju Sakai
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba 305-0801, Japan
| | - Miho Kitamura
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba 305-0801, Japan
| | - Koji Horiba
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba 305-0801, Japan
| | - Atsushi Fujimori
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Hiroshi Kumigashira
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba 305-0801, Japan
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