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Emoto S, Kusunose H, Lin YC, Sun H, Masuda S, Fukamachi S, Suenaga K, Kimura T, Ago H. Synthesis of Few-Layer Hexagonal Boron Nitride for Magnetic Tunnel Junction Application. ACS APPLIED MATERIALS & INTERFACES 2024; 16:31457-31463. [PMID: 38847453 DOI: 10.1021/acsami.4c05289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/22/2024]
Abstract
Hexagonal boron nitride (hBN), a wide-gap two-dimensional (2D) insulator, is an ideal tunneling barrier for many applications because of the atomically flat surface, high crystalline quality, and high stability. Few-layer hBN with a thickness of 1-2 nm is an effective barrier for electron tunneling, but the preparation of few-layer hBN relies on mechanical exfoliation from bulk hBN crystals. Here, we report the large-area growth of few-layer hBN by chemical vapor deposition on ferromagnetic Ni-Fe thin films and its application to tunnel barriers of magnetic tunnel junction (MTJ) devices. Few-layer hBN sheets mainly consisting of two to three layers have been successfully synthesized on a Ni-Fe catalyst at a high growth temperature of 1200 °C. The MTJ devices were fabricated on as-grown hBN by using the Ni-Fe film as the bottom ferromagnetic electrode to avoid contamination and surface oxidation. We found that trilayer hBN gives a higher tunneling magnetoresistance (TMR) ratio than bilayer hBN, resulting in a high TMR ratio up to 10% at ∼10 K.
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Affiliation(s)
- Satoru Emoto
- Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Fukuoka 816-8580, Japan
| | - Hiroki Kusunose
- Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Fukuoka 816-8580, Japan
| | - Yung-Chang Lin
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8565, Japan
| | - Haiming Sun
- The Institute of Scientific and Industrial Research (ISIR-SANKEN), Osaka University, Osaka 567-0047, Japan
| | - Shunsuke Masuda
- Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Fukuoka 816-8580, Japan
| | - Satoru Fukamachi
- Faculty of Engineering Sciences, Kyushu University, Fukuoka 816-8580, Japan
| | - Kazu Suenaga
- The Institute of Scientific and Industrial Research (ISIR-SANKEN), Osaka University, Osaka 567-0047, Japan
| | - Takashi Kimura
- Department of Physics, Kyushu University, 744 Motooka, Fukuoka 819-0395, Japan
| | - Hiroki Ago
- Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Fukuoka 816-8580, Japan
- Faculty of Engineering Sciences, Kyushu University, Fukuoka 816-8580, Japan
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2
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Luo Z, Yu Z, Lu X, Niu W, Yu Y, Yao Y, Tian F, Tan CL, Sun H, Gao L, Qin W, Xu Y, Zhao Q, Song XX. Van der Waals Magnetic Electrode Transfer for Two-Dimensional Spintronic Devices. NANO LETTERS 2024; 24:6183-6191. [PMID: 38728596 DOI: 10.1021/acs.nanolett.4c01885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2024]
Abstract
Two-dimensional (2D) materials are promising candidates for spintronic applications. Maintaining their atomically smooth interfaces during integration of ferromagnetic (FM) electrodes is crucial since conventional metal deposition tends to induce defects at the interfaces. Meanwhile, the difficulties in picking up FM metals with strong adhesion and in achieving conductance match between FM electrodes and spin transport channels make it challenging to fabricate high-quality 2D spintronic devices using metal transfer techniques. Here, we report a solvent-free magnetic electrode transfer technique that employs a graphene layer to assist in the transfer of FM metals. It also serves as part of the FM electrode after transfer for optimizing spin injection, which enables the realization of spin valves with excellent performance based on various 2D materials. In addition to two-terminal devices, we demonstrate that the technique is applicable for four-terminal spin valves with nonlocal geometry. Our results provide a promising future of realizing 2D spintronic applications using the developed magnetic electrode transfer technique.
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Affiliation(s)
- Zhongzhong Luo
- College of Electronic and Optical Engineering & College of Flexible Electronics (Future Technology), State Key Laboratory of Organic Electronics and Information Displays, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
- Guangdong Greater Bay Area Institute of Integrated Circuit and System, Guangzhou 510535, China
| | - Zhihao Yu
- Guangdong Greater Bay Area Institute of Integrated Circuit and System, Guangzhou 510535, China
- College of Integrated Circuit Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
| | - Xiangqian Lu
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
| | - Wei Niu
- School of Science, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
| | - Yao Yu
- College of Integrated Circuit Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
| | - Yu Yao
- Institute of Advanced Materials, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
| | - Fuguo Tian
- Institute of Advanced Materials, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
| | - Chee Leong Tan
- College of Integrated Circuit Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
| | - Huabin Sun
- Guangdong Greater Bay Area Institute of Integrated Circuit and System, Guangzhou 510535, China
- College of Integrated Circuit Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
| | - Li Gao
- School of Science, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
- Institute of Advanced Materials, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
| | - Wei Qin
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
| | - Yong Xu
- Guangdong Greater Bay Area Institute of Integrated Circuit and System, Guangzhou 510535, China
- College of Integrated Circuit Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
| | - Qiang Zhao
- College of Electronic and Optical Engineering & College of Flexible Electronics (Future Technology), State Key Laboratory of Organic Electronics and Information Displays, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
- Institute of Advanced Materials, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
| | - Xiang-Xiang Song
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China
- Suzhou Institute for Advanced Research, University of Science and Technology of China Suzhou 215123, China
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3
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Singh AK, Gao W, Deb P. Tunable long-range spin transport in a van der Waals Fe 3GeTe 2/WSe 2/Fe 3GeTe 2 spin valve. Phys Chem Chem Phys 2024; 26:895-902. [PMID: 38087955 DOI: 10.1039/d3cp04955h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2024]
Abstract
The seamless integration of two-dimensional (2D) ferromagnetic materials with similar or dissimilar materials can widen the scope of low-power spintronics. In this regard, a vertical van der Waals (vdW) heterostructure of 2D ferromagnets with semiconducting transition metal dichalcogenides (TMDCs) forms magnetic junctions with exceptional stability and electrical control. Interestingly, 2D metallic Fe3GeTe2 (FGT) reveals above room temperature Curie temperatures and has large magneto anisotropy due to spin-orbit coupling. In addition, it also possesses topological states and a large Berry curvature. Herein, we designed the FGT/WSe2/FGT vdW heterostructure with a uniform and sharp interface so that FGT could maintain its inherent electronic properties. Also, the uniform thickness of the barrier provides a smooth flow of spins through the junctions as tunneling exponentially decays with an increasing barrier thickness. However, strong energy-dependent spin polarization is crucial for achieving optimum spin valve properties, such as large tunneling magnetoresistance (TMR) along with the manipulation of the magnitude and sign reversal. We have observed a shifting of high-energy localized minority spin states toward low-energy regions, which causes spin polarization fluctuation between -42.5% and 41% over a wide range of bias voltage. This leads to a negative TMR% of ∼-100% at 0.1 V Å-1 and also a large positive TMR% at 0.2 V Å-1 and -0.4 V Å-1. Besides, the system exhibits a highly tunable large anomalous Hall conductivity (AHC) of 626 S cm-1. Interestingly, such unprecedented electronic behaviour with large and switchable spin polarization, anomalous Hall conductivity and TMR can be incorporated into MTJ devices, which provide electrical control and long-range spin transport. Additionally, the system emerges as a standout candidate in low-power spintronic devices (e.g., MRAM and magnetic sensors) owing to its distinctive energy-dependent electronic structure with a wide range of external bias.
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Affiliation(s)
- Anil Kumar Singh
- Advanced Functional Materials Laboratory, Department of Physics, Tezpur University (Central University), Tezpur 784028, India.
| | - Weibo Gao
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 639798, Singapore
| | - Pritam Deb
- Advanced Functional Materials Laboratory, Department of Physics, Tezpur University (Central University), Tezpur 784028, India.
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4
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Zeng X, Ye G, Yang F, Ye Q, Zhang L, Ma B, Liu Y, Xie M, Han G, Hao Y, Luo J, Lu X, Liu Y, Wang X. Proximity Effect-Induced Magnetoresistance Enhancement in a Fe 3GeTe 2/NbSe 2/Fe 3GeTe 2 Magnetic Tunnel Junction. ACS APPLIED MATERIALS & INTERFACES 2023. [PMID: 38050752 DOI: 10.1021/acsami.3c15363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/06/2023]
Abstract
The coupling between van der Waals-layered magnetic and superconducting materials holds the possibility of revealing novel physical mechanisms and realizing spintronic devices with new functionalities. Here, we report on the realization and investigation of a maximum ∼17-fold magnetoresistance (MR) enhancement based on a vertical magnetic tunnel junction of Fe3GeTe2 (FGT)/NbSe2/FGT near the NbSe2 layer's superconducting critical temperature (TC) of 6.8 K. This enhancement is attributed to the band splitting in the atomically thin NbSe2 spacer layer induced by the magnetic proximity effect on the material interfaces. However, the band splitting is strongly suppressed by the interlayer coupling in the thick NbSe2 layer. Correspondingly, the device with a thick NbSe2 layer displays no MR increase near TC but a current dependent on transport properties at extremely low temperatures. This work carefully investigates the mechanism of MR enhancement, paving an efficient way for the modulation of spintronics' properties and the achievement of spin-based integrated circuits.
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Affiliation(s)
- Xiangyu Zeng
- Hangzhou Institute of Technology, Xidian University, Hangzhou 311200, China
- State Key Discipline Laboratory of Wide Band Gap Semiconductor Technology, School of Microelectronics, Xidian University, Xi'an 710071, China
| | - Ge Ye
- Center for Correlated Matter and Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Fazhi Yang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Qikai Ye
- College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou 310027, China
| | - Liang Zhang
- Research Center for Humanoid Sensing and Perception, Zhejiang Lab, Hangzhou 311100, China
| | - Boyang Ma
- College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou 310027, China
| | - Yulu Liu
- College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou 310027, China
| | - Mengwei Xie
- Center for Correlated Matter and Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Genquan Han
- Hangzhou Institute of Technology, Xidian University, Hangzhou 311200, China
- State Key Discipline Laboratory of Wide Band Gap Semiconductor Technology, School of Microelectronics, Xidian University, Xi'an 710071, China
| | - Yue Hao
- Hangzhou Institute of Technology, Xidian University, Hangzhou 311200, China
- State Key Discipline Laboratory of Wide Band Gap Semiconductor Technology, School of Microelectronics, Xidian University, Xi'an 710071, China
| | - Jikui Luo
- College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou 310027, China
| | - Xin Lu
- Center for Correlated Matter and Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Yan Liu
- Hangzhou Institute of Technology, Xidian University, Hangzhou 311200, China
- State Key Discipline Laboratory of Wide Band Gap Semiconductor Technology, School of Microelectronics, Xidian University, Xi'an 710071, China
| | - Xiaozhi Wang
- College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou 310027, China
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5
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Man P, Huang L, Zhao J, Ly TH. Ferroic Phases in Two-Dimensional Materials. Chem Rev 2023; 123:10990-11046. [PMID: 37672768 DOI: 10.1021/acs.chemrev.3c00170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/08/2023]
Abstract
Two-dimensional (2D) ferroics, namely ferroelectric, ferromagnetic, and ferroelastic materials, are attracting rising interest due to their fascinating physical properties and promising functional applications. A variety of 2D ferroic phases, as well as 2D multiferroics and the novel 2D ferrovalleytronics/ferrotoroidics, have been recently predicted by theory, even down to the single atomic layers. Meanwhile, some of them have already been experimentally verified. In addition to the intrinsic 2D ferroics, appropriate stacking, doping, and defects can also artificially regulate the ferroic phases of 2D materials. Correspondingly, ferroic ordering in 2D materials exhibits enormous potential for future high density memory devices, energy conversion devices, and sensing devices, among other applications. In this paper, the recent research progresses on 2D ferroic phases are comprehensively reviewed, with emphasis on chemistry and structural origin of the ferroic properties. In addition, the promising applications of the 2D ferroics for information storage, optoelectronics, and sensing are also briefly discussed. Finally, we envisioned a few possible pathways for the future 2D ferroics research and development. This comprehensive overview on the 2D ferroic phases can provide an atlas for this field and facilitate further exploration of the intriguing new materials and physical phenomena, which will generate tremendous impact on future functional materials and devices.
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Affiliation(s)
- Ping Man
- Department of Chemistry and Center of Super-Diamond & Advanced Films (COSDAF), City University of Hong Kong, Kowloon, Hong Kong 999077, P. R. China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, P. R. China
| | - Lingli Huang
- Department of Chemistry and Center of Super-Diamond & Advanced Films (COSDAF), City University of Hong Kong, Kowloon, Hong Kong 999077, P. R. China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, P. R. China
| | - Jiong Zhao
- Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong 999077, P. R. China
- The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen 518057, P. R. China
| | - Thuc Hue Ly
- Department of Chemistry and Center of Super-Diamond & Advanced Films (COSDAF), City University of Hong Kong, Kowloon, Hong Kong 999077, P. R. China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, P. R. China
- Department of Chemistry and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon, Hong Kong 999077, P. R. China
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6
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Zhu W, Zhu Y, Zhou T, Zhang X, Lin H, Cui Q, Yan F, Wang Z, Deng Y, Yang H, Zhao L, Žutić I, Belashchenko KD, Wang K. Large and tunable magnetoresistance in van der Waals ferromagnet/semiconductor junctions. Nat Commun 2023; 14:5371. [PMID: 37666843 PMCID: PMC10477182 DOI: 10.1038/s41467-023-41077-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 08/23/2023] [Indexed: 09/06/2023] Open
Abstract
Magnetic tunnel junctions (MTJs) with conventional bulk ferromagnets separated by a nonmagnetic insulating layer are key building blocks in spintronics for magnetic sensors and memory. A radically different approach of using atomically-thin van der Waals (vdW) materials in MTJs is expected to boost their figure of merit, the tunneling magnetoresistance (TMR), while relaxing the lattice-matching requirements from the epitaxial growth and supporting high-quality integration of dissimilar materials with atomically-sharp interfaces. We report TMR up to 192% at 10 K in all-vdW Fe3GeTe2/GaSe/Fe3GeTe2 MTJs. Remarkably, instead of the usual insulating spacer, this large TMR is realized with a vdW semiconductor GaSe. Integration of semiconductors into the MTJs offers energy-band-tunability, bias dependence, magnetic proximity effects, and spin-dependent optical-selection rules. We demonstrate that not only the magnitude of the TMR is tuned by the semiconductor thickness but also the TMR sign can be reversed by varying the bias voltages, enabling modulation of highly spin-polarized carriers in vdW semiconductors.
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Affiliation(s)
- Wenkai Zhu
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, 100083, Beijing, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Yingmei Zhu
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, 210093, Nanjing, China
| | - Tong Zhou
- Department of Physics, University at Buffalo, State University of New York, Buffalo, NY, 14260, USA
| | - Xianpeng Zhang
- Department of Physics, University of Basel, Basel, Basel-Stadt, CH-4056, Switzerland
| | - Hailong Lin
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, 100083, Beijing, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Qirui Cui
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, 210093, Nanjing, China
| | - Faguang Yan
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, 100083, Beijing, China
| | - Ziao Wang
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, 100083, Beijing, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Yongcheng Deng
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, 100083, Beijing, China
| | - Hongxin Yang
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, 210093, Nanjing, China.
| | - Lixia Zhao
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, 100083, Beijing, China.
- Tiangong University, 300387, Tianjin, China.
| | - Igor Žutić
- Department of Physics, University at Buffalo, State University of New York, Buffalo, NY, 14260, USA.
| | - Kirill D Belashchenko
- Department of Physics and Astronomy, Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA.
| | - Kaiyou Wang
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, 100083, Beijing, China.
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, 100049, Beijing, China.
- Beijing Academy of Quantum Information Sciences, 100193, Beijing, China.
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7
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El-Kerdi B, Thiaville A, Rohart S, Panigrahy S, Brás N, Sampaio J, Mougin A. Evidence of Strong Dzyaloshinskii-Moriya Interaction at the Cobalt/Hexagonal Boron Nitride Interface. NANO LETTERS 2023; 23:3202-3208. [PMID: 37053437 DOI: 10.1021/acs.nanolett.2c04985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
The Dzyaloshinskii-Moriya interaction (DMI) and perpendicular magnetic anisotropy (PMA) were measured on four series of Co films (1-2.2 nm thick) grown on Pt or Au and covered with h-BN or Cu. Clean h-BN/Co interfaces were obtained by exfoliating h-BN and transferring it onto the Co film in situ in the ultra-high-vacuum evaporation chamber. By comparing h-BN and Cu-covered samples, the DMI induced by the Co/h-BN interface was extracted and found to be comparable in strength to that of the Pt/Co interface, one of the largest known values. The strong observed DMI despite the weak spin-orbit interaction in h-BN supports a Rashba-like origin in agreement with recent theoretical results. Upon combination of it with Pt/Co in Pt/Co/h-BN heterostructures, even stronger PMA and DMI are found which stabilizes skyrmions at room temperature and a low magnetic field.
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Affiliation(s)
- Banan El-Kerdi
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405 Orsay, France
| | - André Thiaville
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405 Orsay, France
| | - Stanislas Rohart
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405 Orsay, France
| | - Sujit Panigrahy
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405 Orsay, France
| | - Nuno Brás
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405 Orsay, France
| | - João Sampaio
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405 Orsay, France
| | - Alexandra Mougin
- Université Paris-Saclay, CNRS, Laboratoire de Physique des Solides, 91405 Orsay, France
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8
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Chen Z, Liu X, Li X, Gao P, Li Z, Zhu W, Wang H, Li X. Large tunneling magnetoresistance in spin-filtering 1T-MnSe 2/h-BN van der Waals magnetic tunnel junction. NANOSCALE 2023; 15:8447-8455. [PMID: 37097089 DOI: 10.1039/d3nr00045a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The magnetic tunnel junction (MTJ), one of the most prominent spintronic devices, has been widely utilized for memory and computation systems. Electrical writing is considered as a practical method to enhance the performance of MTJs with high circuit integration density and ultralow-power consumption. Meanwhile, a large tunneling magnetoresistance (TMR), especially at the non-equilibrium state, is desirable for the improvement of the sensitivity and stability of MTJ devices. However, achieving both aspects efficiently is still challenging. Here, we propose a two-dimensional (2D) MTJ of 1T-MnSe2/h-BN/1T-MnSe2/h-BN/1T-MnSe2 with efficient electrical writing, reliable reading operations and high potential to work at room temperature. First, for this proposed MTJ with a symmetrical structure and an antiparallel magnetic state, the degeneracy of the energy could be broken by an electric field, resulting in a 180° magnetization reversal. A first principles study confirms that the magnetization of the center 1T-MnSe2 layer could be reversed by changing the direction of the electric field, when the magnetic configurations of the two outer 1T-MnSe2 layers are fixed in the antiparallel state. Furthermore, we report a theoretical spin-related transport investigation of the MTJ at the non-equilibrium state. Thanks to the half-metallicity of 1T-MnSe2, TMR ratios reach very satisfactory values of 2.56 × 103% with the magnetization information written by an electric field at room temperature. In addition, the performance of the TMR effect exhibits good stability even when the bias voltage increases gradually. Our theoretical findings show that this proposed MTJ is a promising high performance spintronic device and could promote the design of ultralow-power spintronic devices.
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Affiliation(s)
- Zhao Chen
- Department of Physics, Hefei University of Technology, Hefei, Anhui 230009, China.
| | - Xiaofeng Liu
- Department of Physics, Hefei University of Technology, Hefei, Anhui 230009, China.
| | - Xingxing Li
- Department of Chemical Physics, Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China.
| | - Pengfei Gao
- Interdisciplinary Center for Fundamental and Frontier Sciences, Nanjing University of Science and Technology, Jiangyin, Jiangsu, 214443, China
| | - ZhongJun Li
- Department of Physics, Hefei University of Technology, Hefei, Anhui 230009, China.
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Shanxi University, Taiyuan 030006, China
| | - Weiduo Zhu
- Department of Physics, Hefei University of Technology, Hefei, Anhui 230009, China.
| | - Haidi Wang
- Department of Physics, Hefei University of Technology, Hefei, Anhui 230009, China.
| | - Xiangyang Li
- School of Materials Science and Engineering, Anhui University, Hefei, Anhui 230601, China
- Department of Chemical Physics, Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China.
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9
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Luo Z, Song X, Liu X, Lu X, Yao Y, Zeng J, Li Y, He D, Zhao H, Gao L, Yu Z, Niu W, Sun H, Xu Y, Liu S, Qin W, Zhao Q. Revealing the key role of molecular packing on interface spin polarization at two-dimensional limit in spintronic devices. SCIENCE ADVANCES 2023; 9:eade9126. [PMID: 37018394 PMCID: PMC10075958 DOI: 10.1126/sciadv.ade9126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 03/03/2023] [Indexed: 06/19/2023]
Abstract
Understanding spinterfaces between magnetic metals and organic semiconductors is essential to unlock the great potentials that organic materials host for spintronic applications. Although plenty of efforts have been devoted to studying organic spintronic devices, exploring the role of metal/molecule spinterfaces at two-dimensional limit remains challenging because of excessive disorders and traps at the interfaces. Here, we demonstrate atomically smooth metal/molecule interfaces through nondestructively transferring magnetic electrodes on epitaxial grown single-crystalline layered organic films. Using such high-quality interfaces, we investigate spin injection of spin-valve devices based on organic films of different layers, in which molecules are packed in different manners. We find that the measured magnetoresistance and the estimated spin polarization increase markedly for bilayer devices compared with their monolayer counterparts. These observations reveal the key role of molecular packing on spin polarization, which is supported by density functional theory calculations. Our findings provide promising routes toward designing spinterfaces for organic spintronic devices.
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Affiliation(s)
- Zhongzhong Luo
- College of Electronic and Optical Engineering and College of Flexible Electronics (Future Technology), State Key Laboratory of Organic Electronics and Information Displays, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
- National Laboratory of Solid State Microstructures, School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Xiangxiang Song
- National Laboratory of Solid State Microstructures, School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
- Suzhou Institute for Advanced Research, University of Science and Technology of China, Suzhou 215123, China
| | - Xiaolong Liu
- School of New Energy, North China Electric Power University, Beijing 102206, China
| | - Xiangqian Lu
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
| | - Yu Yao
- Institute of Advanced Materials, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
| | - Junpeng Zeng
- National Laboratory of Solid State Microstructures, School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Yating Li
- National Laboratory of Solid State Microstructures, School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Daowei He
- National Laboratory of Solid State Microstructures, School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Huijuan Zhao
- Institute of Advanced Materials, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
| | - Li Gao
- Institute of Advanced Materials, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
| | - Zhihao Yu
- National Laboratory of Solid State Microstructures, School of Electronic Science and Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
- College of Integrated Circuit Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
| | - Wei Niu
- New Energy Technology Engineering Laboratory of Jiangsu Province and School of Science, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
| | - Huabin Sun
- College of Integrated Circuit Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
| | - Yong Xu
- College of Integrated Circuit Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
- Guangdong Greater Bay Area Institute of Integrated Circuit and System, Guangzhou 510535, China
| | - Shujuan Liu
- Institute of Advanced Materials, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
| | - Wei Qin
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
| | - Qiang Zhao
- College of Electronic and Optical Engineering and College of Flexible Electronics (Future Technology), State Key Laboratory of Organic Electronics and Information Displays, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
- Institute of Advanced Materials, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
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10
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Zatko V, Galceran R, Galbiati M, Peiro J, Godel F, Kern LM, Perconte D, Ibrahim F, Hallal A, Chshiev M, Martinez B, Frontera C, Balcells L, Kidambi PR, Robertson J, Hofmann S, Collin S, Petroff F, Martin MB, Dlubak B, Seneor P. Artificial Graphene Spin Polarized Electrode for Magnetic Tunnel Junctions. NANO LETTERS 2023; 23:34-41. [PMID: 36535029 PMCID: PMC10009810 DOI: 10.1021/acs.nanolett.2c03113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 11/24/2022] [Indexed: 06/17/2023]
Abstract
2D materials offer the ability to expose their electronic structure to manipulations by a proximity effect. This could be harnessed to craft properties of 2D interfaces and van der Waals heterostructures in devices and quantum materials. We explore the possibility to create an artificial spin polarized electrode from graphene through proximity interaction with a ferromagnetic insulator to be used in a magnetic tunnel junction (MTJ). Ferromagnetic insulator/graphene artificial electrodes were fabricated and integrated in MTJs based on spin analyzers. Evidence of the emergence of spin polarization in proximitized graphene layers was observed through the occurrence of tunnel magnetoresistance. We deduced a spin dependent splitting of graphene's Dirac band structure (∼15 meV) induced by the proximity effect, potentially leading to full spin polarization and opening the way to gating. The extracted spin signals illustrate the potential of 2D quantum materials based on proximity effects to craft spintronics functionalities, from vertical MTJs memory cells to logic circuits.
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Affiliation(s)
- Victor Zatko
- Unité
Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767Palaiseau, France
| | - Regina Galceran
- Unité
Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767Palaiseau, France
- CSIC
and BIST, Campus UAB, Catalan Institute
of Nanoscience and Nanotechnology (ICN2), Bellaterra, 08193Barcelona, Spain
| | - Marta Galbiati
- Unité
Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767Palaiseau, France
| | - Julian Peiro
- Unité
Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767Palaiseau, France
| | - Florian Godel
- Unité
Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767Palaiseau, France
| | - Lisa-Marie Kern
- Unité
Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767Palaiseau, France
| | - David Perconte
- Unité
Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767Palaiseau, France
| | - Fatima Ibrahim
- Univ.
Grenoble Alpes, CEA, CNRS, Spintec, 38000Grenoble, France
| | - Ali Hallal
- Univ.
Grenoble Alpes, CEA, CNRS, Spintec, 38000Grenoble, France
| | - Mairbek Chshiev
- Univ.
Grenoble Alpes, CEA, CNRS, Spintec, 38000Grenoble, France
- Institut
Universitaire de France, 75231Paris, France
| | - Benjamin Martinez
- Institut
de Ciencia de Materials de Barcelona, ICMAB-CSIC,
Campus UAB, 08193Bellaterra, Spain
| | - Carlos Frontera
- Institut
de Ciencia de Materials de Barcelona, ICMAB-CSIC,
Campus UAB, 08193Bellaterra, Spain
| | - Lluìs Balcells
- Institut
de Ciencia de Materials de Barcelona, ICMAB-CSIC,
Campus UAB, 08193Bellaterra, Spain
| | - Piran R. Kidambi
- Department
of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee37212, United States
| | - John Robertson
- Department
of Engineering, University of Cambridge, CambridgeCB3 0FA, United Kingdom
| | - Stephan Hofmann
- Department
of Engineering, University of Cambridge, CambridgeCB3 0FA, United Kingdom
| | - Sophie Collin
- Unité
Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767Palaiseau, France
| | - Frédéric Petroff
- Unité
Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767Palaiseau, France
| | - Marie-Blandine Martin
- Unité
Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767Palaiseau, France
| | - Bruno Dlubak
- Unité
Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767Palaiseau, France
| | - Pierre Seneor
- Unité
Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767Palaiseau, France
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11
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Min KH, Lee DH, Choi SJ, Lee IH, Seo J, Kim DW, Ko KT, Watanabe K, Taniguchi T, Ha DH, Kim C, Shim JH, Eom J, Kim JS, Jung S. Tunable spin injection and detection across a van der Waals interface. NATURE MATERIALS 2022; 21:1144-1149. [PMID: 35927432 DOI: 10.1038/s41563-022-01320-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 06/24/2022] [Indexed: 06/15/2023]
Abstract
Van der Waals heterostructures with two-dimensional magnets offer a magnetic junction with an atomically sharp and clean interface. This attribute ensures that the magnetic layers maintain their intrinsic spin-polarized electronic states and spin-flipping scattering processes at a minimum level, a trait that can expand spintronic device functionalities. Here, using a van der Waals assembly of ferromagnetic Fe3GeTe2 with non-magnetic hexagonal boron nitride and WSe2 layers, we demonstrate electrically tunable, highly transparent spin injection and detection across the van der Waals interfaces. By varying an electrical bias, the net spin polarization of the injected carriers can be modulated and reversed in polarity, which leads to sign changes of the tunnelling magnetoresistance. We attribute the spin polarization reversals to sizable contributions from high-energy localized spin states in the metallic ferromagnet, so far inaccessible in conventional magnetic junctions. Such tunability of the spin-valve operations opens a promising route for the electronic control of next-generation low-dimensional spintronic device applications.
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Affiliation(s)
- Keun-Hong Min
- Interdisciplinary Materials Measurement Institute, Korea Research Institute of Standards and Science, Daejeon, Republic of Korea
- Department of Physics and Astronomy, Sejong University, Seoul, Republic of Korea
| | - Duk Hyun Lee
- Interdisciplinary Materials Measurement Institute, Korea Research Institute of Standards and Science, Daejeon, Republic of Korea
| | - Sang-Jun Choi
- Institute for Theoretical Physics and Astrophysics, University of Würzburg, Würzburg, Germany
| | - In-Ho Lee
- Interdisciplinary Materials Measurement Institute, Korea Research Institute of Standards and Science, Daejeon, Republic of Korea
| | - Junho Seo
- Department of Physics, Pohang University of Science and Technology, Pohang, Republic of Korea
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science, Pohang, Republic of Korea
| | - Dong Wook Kim
- Department of Chemistry, Pohang University of Science and Technology, Pohang, Republic of Korea
| | - Kyung-Tae Ko
- Research Center for Materials Analysis, Korea Basic Science Institute, Daejeon, Republic of Korea
| | - Kenji Watanabe
- Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba, Japan
| | - Takashi Taniguchi
- Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba, Japan
| | - Dong Han Ha
- Interdisciplinary Materials Measurement Institute, Korea Research Institute of Standards and Science, Daejeon, Republic of Korea
| | - Changyoung Kim
- Department of Physics and Astronomy, Seoul National University, Seoul, Republic of Korea
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, Republic of Korea
| | - Ji Hoon Shim
- Department of Physics, Pohang University of Science and Technology, Pohang, Republic of Korea
- Department of Chemistry, Pohang University of Science and Technology, Pohang, Republic of Korea
| | - Jonghwa Eom
- Department of Physics and Astronomy, Sejong University, Seoul, Republic of Korea.
| | - Jun Sung Kim
- Department of Physics, Pohang University of Science and Technology, Pohang, Republic of Korea.
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science, Pohang, Republic of Korea.
| | - Suyong Jung
- Interdisciplinary Materials Measurement Institute, Korea Research Institute of Standards and Science, Daejeon, Republic of Korea.
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12
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Zatko V, Dubois SMM, Godel F, Galbiati M, Peiro J, Sander A, Carretero C, Vecchiola A, Collin S, Bouzehouane K, Servet B, Petroff F, Charlier JC, Martin MB, Dlubak B, Seneor P. Almost Perfect Spin Filtering in Graphene-Based Magnetic Tunnel Junctions. ACS NANO 2022; 16:14007-14016. [PMID: 36068013 PMCID: PMC9527810 DOI: 10.1021/acsnano.2c03625] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 07/14/2022] [Indexed: 06/15/2023]
Abstract
We report on large spin-filtering effects in epitaxial graphene-based spin valves, strongly enhanced in our specific multilayer case. Our results were obtained by the effective association of chemical vapor deposited (CVD) multilayer graphene with a high quality epitaxial Ni(111) ferromagnetic spin source. We highlight that the Ni(111) spin source electrode crystallinity and metallic state are preserved and stabilized by multilayer graphene CVD growth. Complete nanometric spin valve junctions are fabricated using a local probe indentation process, and spin properties are extracted from the graphene-protected ferromagnetic electrode through the use of a reference Al2O3/Co spin analyzer. Strikingly, spin-transport measurements in these structures give rise to large negative tunnel magneto-resistance TMR = -160%, pointing to a particularly large spin polarization for the Ni(111)/Gr interface PNi/Gr, evaluated up to -98%. We then discuss an emerging physical picture of graphene-ferromagnet systems, sustained both by experimental data and ab initio calculations, intimately combining efficient spin filtering effects arising (i) from the bulk band structure of the graphene layers purifying the extracted spin direction, (ii) from the hybridization effects modulating the amplitude of spin polarized scattering states over the first few graphene layers at the interface, and (iii) from the epitaxial interfacial matching of the graphene layers with the spin-polarized Ni surface selecting well-defined spin polarized channels. Importantly, these main spin selection effects are shown to be either cooperating or competing, explaining why our transport results were not observed before. Overall, this study unveils a path to harness the full potential of low Resitance.Area (RA) graphene interfaces in efficient spin-based devices.
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Affiliation(s)
- Victor Zatko
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Simon M.-M. Dubois
- Institute
of Condensed Matter and Nanosciences (IMCN), Université Catholique de Louvain (UCLouvain), B-1348 Louvain-la-Neuve, Belgium
| | - Florian Godel
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Marta Galbiati
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Julian Peiro
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Anke Sander
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Cécile Carretero
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Aymeric Vecchiola
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Sophie Collin
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Karim Bouzehouane
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Bernard Servet
- Thales
Research and Technology, 1 avenue Augustin Fresnel, 91767 Palaiseau, France
| | - Frédéric Petroff
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Jean-Christophe Charlier
- Institute
of Condensed Matter and Nanosciences (IMCN), Université Catholique de Louvain (UCLouvain), B-1348 Louvain-la-Neuve, Belgium
| | - Marie-Blandine Martin
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Bruno Dlubak
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
| | - Pierre Seneor
- Unité
Mixte de Physique, CNRS, Thales, Université
Paris-Saclay, 91767 Palaiseau, France
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13
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Two-dimensional materials prospects for non-volatile spintronic memories. Nature 2022; 606:663-673. [PMID: 35732761 DOI: 10.1038/s41586-022-04768-0] [Citation(s) in RCA: 63] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 04/19/2022] [Indexed: 01/12/2023]
Abstract
Non-volatile magnetic random-access memories (MRAMs), such as spin-transfer torque MRAM and next-generation spin-orbit torque MRAM, are emerging as key to enabling low-power technologies, which are expected to spread over large markets from embedded memories to the Internet of Things. Concurrently, the development and performances of devices based on two-dimensional van der Waals heterostructures bring ultracompact multilayer compounds with unprecedented material-engineering capabilities. Here we provide an overview of the current developments and challenges in regard to MRAM, and then outline the opportunities that can arise by incorporating two-dimensional material technologies. We highlight the fundamental properties of atomically smooth interfaces, the reduced material intermixing, the crystal symmetries and the proximity effects as the key drivers for possible disruptive improvements for MRAM at advanced technology nodes.
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14
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Deng YX, Chen SZ, Hong J, Jia PZ, Zhang Y, Yu X, Chen KQ. Perfect spin-filtering effect in molecular junctions based on half-metallic penta-hexa-graphene nanoribbons. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:285302. [PMID: 35477168 DOI: 10.1088/1361-648x/ac6b0a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 04/27/2022] [Indexed: 06/14/2023]
Abstract
The design and control of spintronic devices is a research hotspot in the field of electronics, and pure carbon-based materials provide new opportunities for the construction of electronic devices with excellent performance. Using density functional theory in combination with nonequilibrium Green's functions method, we design spin filter devices based on Penta-hexa-graphene (PHG) nanoribbons-a carbon nanomaterial in which the intrinsic magnetic moments combines with edge effects leading to a half-metallic property. Spin-resolved electronic transport studies show that such carbon-based devices can achieve nearly 100% spin filtering effect at low bias voltages. Such SEF can resist the influence of hydrogen passivation at different positions, but hardly survive under a hydrogen-rich environment. Our analysis show that the perfect SEF transport properties are caused by the magnetic and electronic properties of PHG nanoribbons, especially the magnetic moments on the quasi-sp3carbons. These interesting results indicate that PHG nanomaterials have very prominent application prospects in future spintronic devices.
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Affiliation(s)
- Yuan-Xiang Deng
- School of Science, Hunan Institute of Technology, Hengyang 421002, People's Republic of China
- Department of Applied Physics, School of Physics and Electronics, Hunan University, Changsha 410082, People's Republic of China
| | - Shi-Zhang Chen
- Department of Applied Physics, College of Electronics Engineering, South China Agricultural University, Guangzhou, Guangdong 510642, People's Republic of China
| | - Jun Hong
- School of Electrical Information Engineering, Hunan Institute of Technology, Hengyang 421002, People's Republic of China
| | - Pin-Zhen Jia
- School of Science, Hunan Institute of Technology, Hengyang 421002, People's Republic of China
| | - Yong Zhang
- School of Science, Hunan Institute of Technology, Hengyang 421002, People's Republic of China
| | - Xia Yu
- School of Electrical Information Engineering, Hunan Institute of Technology, Hengyang 421002, People's Republic of China
| | - Ke-Qiu Chen
- Department of Applied Physics, School of Physics and Electronics, Hunan University, Changsha 410082, People's Republic of China
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15
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Pal A, Zhang S, Chavan T, Agashiwala K, Yeh CH, Cao W, Banerjee K. Quantum-Engineered Devices Based on 2D Materials for Next-Generation Information Processing and Storage. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022:e2109894. [PMID: 35468661 DOI: 10.1002/adma.202109894] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 04/11/2022] [Indexed: 06/14/2023]
Abstract
As an approximation to the quantum state of solids, the band theory, developed nearly seven decades ago, fostered the advance of modern integrated solid-state electronics, one of the most successful technologies in the history of human civilization. Nonetheless, their rapidly growing energy consumption and accompanied environmental issues call for more energy-efficient electronics and optoelectronics, which necessitate the exploration of more advanced quantum mechanical effects, such as band-to-band tunneling, spin-orbit coupling, spin-valley locking, and quantum entanglement. The emerging 2D layered materials, featured by their exotic electrical, magnetic, optical, and structural properties, provide a revolutionary low-dimensional and manufacture-friendly platform (and many more opportunities) to implement these quantum-engineered devices, compared to the traditional electronic materials system. Here, the progress in quantum-engineered devices is reviewed and the opportunities/challenges of exploiting 2D materials are analyzed to highlight their unique quantum properties that enable novel energy-efficient devices, and useful insights to quantum device engineers and 2D-material scientists are provided.
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Affiliation(s)
- Arnab Pal
- ECE Department, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Shuo Zhang
- ECE Department, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA
- College of ISEE, Zhejiang University, Hangzhou, 310027, China
| | - Tanmay Chavan
- ECE Department, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Kunjesh Agashiwala
- ECE Department, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Chao-Hui Yeh
- ECE Department, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Wei Cao
- ECE Department, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Kaustav Banerjee
- ECE Department, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA
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16
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Zhang Z, Guo Y, Robertson J. Reduced Fermi Level Pinning at Physisorptive Sites of Moire-MoS 2/Metal Schottky Barriers. ACS APPLIED MATERIALS & INTERFACES 2022; 14:11903-11909. [PMID: 35220717 PMCID: PMC9098114 DOI: 10.1021/acsami.1c23918] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 02/18/2022] [Indexed: 06/14/2023]
Abstract
Weaker Fermi level pinning (FLP) at the Schottky barriers of 2D semiconductors is electrically desirable as this would allow a minimizing of contact resistances, which presently limit device performances. Existing contacts on MoS2 have a strong FLP with a small pinning factor of only ∼0.1. Here, we show that Moire interfaces can stabilize physisorptive sites at the Schottky barriers with a much weaker interaction without significantly lengthening the bonds. This increases the pinning factor up to ∼0.37 and greatly reduces the n-type Schottky barrier height to ∼0.2 eV for certain metals such as In and Ag, which can have physisorptive sites. This then accounts for the low contact resistance of these metals as seen experimentally. Such physisorptive interfaces can be extended to similar systems to better control SBHs in highly scaled 2D devices.
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Affiliation(s)
- Zhaofu Zhang
- Department
of Engineering, University of Cambridge, Cambridge CB3 0FA, U.K.
| | - Yuzheng Guo
- School
of Electrical Engineering, Wuhan University, Wuhan 430072, China
| | - John Robertson
- Department
of Engineering, University of Cambridge, Cambridge CB3 0FA, U.K.
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17
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Larionov KV, Pais Pereda JJ, Sorokin PB. A DFT study on magnetic interfaces based on half-metallic Co 2FeGe 1/2Ga 1/2 with h-BN and MoSe 2 monolayers. Phys Chem Chem Phys 2022; 24:1023-1028. [PMID: 34927637 DOI: 10.1039/d1cp04806f] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
A large variety of recently predicted and synthesized 2D materials significantly broaden the capabilities of magnetic interface design for spintronic applications. Their diverse structural and electronic properties allow fine adjustment of interfacial interactions between the electrode and spacer materials providing robust and effective spin transport. Based on recent experimental results, here we present a theoretical study of novel interfaces formed by a half-metallic Co2FeGe1/2Ga1/2 (CFGG) substrate with h-BN or MoSe2 monolayer on its top. By means of the DFT approach, the structural, magnetic and electronic properties are studied for the Co- and FeGeGa termination of the CFGG surface. The observed large spin polarization in the vicinity of the interface and robust magnetization exhibit the potential of 2D materials/CFGG heterostructures for spintronic applications.
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Affiliation(s)
- Konstantin V Larionov
- National University of Science and Technology "MISiS", Moscow 119049, Russian Federation. .,Moscow Institute of Physics and Technology (National Research University), 141701, 9 Institutskiy pereulok, Dolgoprudny, Moscow Region, Russian Federation
| | - J J Pais Pereda
- National University of Science and Technology "MISiS", Moscow 119049, Russian Federation.
| | - Pavel B Sorokin
- National University of Science and Technology "MISiS", Moscow 119049, Russian Federation. .,Moscow Institute of Physics and Technology (National Research University), 141701, 9 Institutskiy pereulok, Dolgoprudny, Moscow Region, Russian Federation
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18
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Liu Y, Guo Y, Wu C, Xie Y. Spin-Dependent Transport at 2D Solids: From Nonmagnetic Layers to Ferromagnetic van der Waals Structures. J Phys Chem Lett 2021; 12:9730-9740. [PMID: 34590853 DOI: 10.1021/acs.jpclett.1c02047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Spintronics is a promising alternative to the conventional silicon transistor-based electronics that are gradually approaching their physical limitations. Ultrathin two-dimensional van der Waals (vdW) materials (2D materials) with controllable spin degrees of freedom are recognized as extremely promising spintronic materials in architectures for the post-Moore era. In this Perspective, we review recent progress on spin-dependent transport behaviors (SDTBs) confined at the 2D scale, which are the mainstream paradigms for spintronic devices. We first present the mechanism and the key factors of SDTBs in 2D nonmagnetic materials-based hybrid devices. Then, some chemical modulation strategies for inducing short-range magnetic order and magneto-electric performance into 2D nonmagnetic materials are discussed. Furthermore, we concentrate on introducing intriguing SDTBs in 2D long-range ferromagnetic materials-based vdW devices. Finally, we highlight the current challenges in the study of spin-dependent transport of 2D modified materials and 2D material-based spintronic devices, in the hope of accelerating their applications.
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Affiliation(s)
- Yang Liu
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Center for Excellence in Nanoscience, and CAS Key Laboratory of Mechanical Behavior and Design of Materials, University of Science and Technology of China, Hefei 230026, P.R. China
| | - Yuqiao Guo
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Center for Excellence in Nanoscience, and CAS Key Laboratory of Mechanical Behavior and Design of Materials, University of Science and Technology of China, Hefei 230026, P.R. China
- Institute of Energy, Hefei Comprehensive National Science Center, Hefei 230031, P.R. China
| | - Changzheng Wu
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Center for Excellence in Nanoscience, and CAS Key Laboratory of Mechanical Behavior and Design of Materials, University of Science and Technology of China, Hefei 230026, P.R. China
- Institute of Energy, Hefei Comprehensive National Science Center, Hefei 230031, P.R. China
| | - Yi Xie
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Center for Excellence in Nanoscience, and CAS Key Laboratory of Mechanical Behavior and Design of Materials, University of Science and Technology of China, Hefei 230026, P.R. China
- Institute of Energy, Hefei Comprehensive National Science Center, Hefei 230031, P.R. China
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19
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Lu H, Guo Y, Robertson J. Ab Initio Study of Hexagonal Boron Nitride as the Tunnel Barrier in Magnetic Tunnel Junctions. ACS APPLIED MATERIALS & INTERFACES 2021; 13:47226-47235. [PMID: 34559966 DOI: 10.1021/acsami.1c13583] [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
Two-dimensional hexagonal boron nitride (h-BN) is studied as a tunnel barrier in magnetic tunnel junctions (MTJs) as a possible alternative to MgO. The tunnel magnetoresistance (TMR) of such MTJs is calculated as a function of whether the interface involves the chemi- or physisorptive site of h-BN atoms on the metal electrodes, Fe, Co, or Ni. It is found that the physisorptive site on average produces higher TMR values, whereas the chemisorptive site has the greater binding energy but lower TMR. It is found that alloying the electrodes with an inert metal-like Pt can induce the preferred absorption site on Co to become a physisorptive site, enabling a higher TMR value. It is found that the choice of physisorptive sites of each element gives more Schottky-like dependence of their Schottky barrier heights on the metal work function.
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Affiliation(s)
- Haichang Lu
- School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, China
- Engineering Department, Cambridge University, Cambridge CB2 1PZ, U.K
| | - Yuzheng Guo
- Engineering Department, Cambridge University, Cambridge CB2 1PZ, U.K
- School of Engineering, Swansea University, Swansea SA1 8EN, U.K
| | - John Robertson
- Engineering Department, Cambridge University, Cambridge CB2 1PZ, U.K
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20
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Hallal A, Liang J, Ibrahim F, Yang H, Fert A, Chshiev M. Rashba-Type Dzyaloshinskii-Moriya Interaction, Perpendicular Magnetic Anisotropy, and Skyrmion States at 2D Materials/Co Interfaces. NANO LETTERS 2021; 21:7138-7144. [PMID: 34432472 DOI: 10.1021/acs.nanolett.1c01713] [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
We report a significant Dzyaloshinskii-Moriya interaction (DMI) and perpendicular magnetic anisotropy (PMA) at interfaces comprising hexagonal boron nitride (h-BN) and Co. By comparing the behavior of these phenomena at graphene/Co and h-BN/Co interfaces, it is found that the DMI in the latter increases as a function of Co thickness and beyond three monolayers stabilizes with 1 order of magnitude larger values compared to those at graphene/Co, where the DMI shows opposite decreasing behavior. Meanwhile, the PMA for both systems shows similar trends with larger values for graphene/Co and no significant variations for all thickness ranges of Co. Furthermore, using micromagnetic simulations we demonstrate that such significant DMI and PMA values remaining stable over a large range of Co thickness give rise to the formation of skyrmions with small applied external fields. These findings open up further possibilities toward integrating two-dimensional (2D) materials in spin-orbitronics devices.
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Affiliation(s)
- Ali Hallal
- Univ. Grenoble Alpes, CEA, CNRS, Spintec, Grenoble 38000, France
| | - Jinghua Liang
- Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Fatima Ibrahim
- Univ. Grenoble Alpes, CEA, CNRS, Spintec, Grenoble 38000, France
| | - Hongxin Yang
- Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Albert Fert
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, Palaiseau 91767, France
| | - Mairbek Chshiev
- Univ. Grenoble Alpes, CEA, CNRS, Spintec, Grenoble 38000, France
- Institut Universitaire de France, Paris 75231, France
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21
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Zatko V, Dubois SMM, Godel F, Carrétéro C, Sander A, Collin S, Galbiati M, Peiro J, Panciera F, Patriarche G, Brus P, Servet B, Charlier JC, Martin MB, Dlubak B, Seneor P. Band-Gap Landscape Engineering in Large-Scale 2D Semiconductor van der Waals Heterostructures. ACS NANO 2021; 15:7279-7289. [PMID: 33755422 DOI: 10.1021/acsnano.1c00544] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We present a growth process relying on pulsed laser deposition for the elaboration of complex van der Waals heterostructures on large scales, at a 400 °C CMOS-compatible temperature. Illustratively, we define a multilayer quantum well geometry through successive in situ growths, leading to WSe2 being encapsulated into WS2 layers. The structural constitution of the quantum well geometry is confirmed by Raman spectroscopy combined with transmission electron microscopy. The large-scale high homogeneity of the resulting 2D van der Waals heterostructure is also validated by macro- and microscale Raman mappings. We illustrate the benefit of this integrative in situ approach by showing the structural preservation of even the most fragile 2D layers once encapsulated in a van der Waals heterostructure. Finally, we fabricate a vertical tunneling device based on these large-scale layers and discuss the clear signature of electronic transport controlled by the quantum well configuration with ab initio calculations in support. The flexibility of this direct growth approach, with multilayer stacks being built in a single run, allows for the definition of complex 2D heterostructures barely accessible with usual exfoliation or transfer techniques of 2D materials. Reminiscent of the III-V semiconductors' successful exploitation, our approach unlocks virtually infinite combinations of large 2D material families in any complex van der Waals heterostructure design.
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Affiliation(s)
- Victor Zatko
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
| | - Simon Mutien-Marie Dubois
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
- Institute of Condensed Matter and Nanosciences (IMCN), Université Catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium
| | - Florian Godel
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
| | - Cécile Carrétéro
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
| | - Anke Sander
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
| | - Sophie Collin
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
| | - Marta Galbiati
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
| | - Julian Peiro
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
| | - Federico Panciera
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, 91120 Palaiseau, France
| | - Gilles Patriarche
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, 91120 Palaiseau, France
| | - Pierre Brus
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
- Thales Research and Technology, 1 Avenue Augustin Fresnel, 91767 Palaiseau, France
| | - Bernard Servet
- Thales Research and Technology, 1 Avenue Augustin Fresnel, 91767 Palaiseau, France
| | - Jean-Christophe Charlier
- Institute of Condensed Matter and Nanosciences (IMCN), Université Catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium
| | - Marie-Blandine Martin
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
| | - Bruno Dlubak
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
| | - Pierre Seneor
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
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22
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Och M, Martin MB, Dlubak B, Seneor P, Mattevi C. Synthesis of emerging 2D layered magnetic materials. NANOSCALE 2021; 13:2157-2180. [PMID: 33475647 DOI: 10.1039/d0nr07867k] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
van der Waals atomically thin magnetic materials have been recently discovered. They have attracted enormous attention as they present unique magnetic properties, holding potential to tailor spin-based device properties and enable next generation data storage and communication devices. To fully understand the magnetism in two-dimensions, the synthesis of 2D materials over large areas with precise thickness control has to be accomplished. Here, we review the recent advancements in the synthesis of these materials spanning from metal halides, transition metal dichalcogenides, metal phosphosulphides, to ternary metal tellurides. We initially discuss the emerging device concepts based on magnetic van der Waals materials including what has been achieved with graphene. We then review the state of the art of the synthesis of these materials and we discuss the potential routes to achieve the synthesis of wafer-scale atomically thin magnetic materials. We discuss the synthetic achievements in relation to the structural characteristics of the materials and we scrutinise the physical properties of the precursors in relation to the synthesis conditions. We highlight the challenges related to the synthesis of 2D magnets and we provide a perspective for possible advancement of available synthesis methods to respond to the need for scalable production and high materials quality.
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Affiliation(s)
- Mauro Och
- Department of Materials, Imperial College London, SW72AZ London, UK.
| | - Marie-Blandine Martin
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
| | - Bruno Dlubak
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
| | - Pierre Seneor
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
| | - Cecilia Mattevi
- Department of Materials, Imperial College London, SW72AZ London, UK.
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23
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Piquemal-Banci M, Galceran R, Dubois SMM, Zatko V, Galbiati M, Godel F, Martin MB, Weatherup RS, Petroff F, Fert A, Charlier JC, Robertson J, Hofmann S, Dlubak B, Seneor P. Spin filtering by proximity effects at hybridized interfaces in spin-valves with 2D graphene barriers. Nat Commun 2020; 11:5670. [PMID: 33168805 PMCID: PMC7652852 DOI: 10.1038/s41467-020-19420-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 10/12/2020] [Indexed: 11/09/2022] Open
Abstract
We report on spin transport in state-of-the-art epitaxial monolayer graphene based 2D-magnetic tunnel junctions (2D-MTJs). In our measurements, supported by ab-initio calculations, the strength of interaction between ferromagnetic electrodes and graphene monolayers is shown to fundamentally control the resulting spin signal. In particular, by switching the graphene/ferromagnet interaction, spin transport reveals magneto-resistance signal MR > 80% in junctions with low resistance × area products. Descriptions based only on a simple K-point filtering picture (i.e. MR increase with the number of layers) are not sufficient to predict the behavior of our devices. We emphasize that hybridization effects need to be taken into account to fully grasp the spin properties (such as spin dependent density of states) when 2D materials are used as ultimately thin interfaces. While this is only a first demonstration, we thus introduce the fruitful potential of spin manipulation by proximity effect at the hybridized 2D material / ferromagnet interface for 2D-MTJs.
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Affiliation(s)
- Maëlis Piquemal-Banci
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - Regina Galceran
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - Simon M-M Dubois
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
- Institute of Condensed Matter and Nanosciences (IMCN), Université Catholique de Louvain, B-1348, Louvain-la-Neuve, Belgium
| | - Victor Zatko
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - Marta Galbiati
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - Florian Godel
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - Marie-Blandine Martin
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
- Department of Engineering, University of Cambridge, Cambridge, CB21PZ, UK
| | - Robert S Weatherup
- School of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
- University of Manchester at Harwell, Diamond Light Source, Didcot, Oxfordshire, OX11 0DE, UK
| | - Frédéric Petroff
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - Albert Fert
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France
| | - Jean-Christophe Charlier
- Institute of Condensed Matter and Nanosciences (IMCN), Université Catholique de Louvain, B-1348, Louvain-la-Neuve, Belgium
| | - John Robertson
- Department of Engineering, University of Cambridge, Cambridge, CB21PZ, UK
| | - Stephan Hofmann
- Department of Engineering, University of Cambridge, Cambridge, CB21PZ, UK
| | - Bruno Dlubak
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France.
| | - Pierre Seneor
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France.
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24
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Liu Y, Zeng C, Zhong J, Ding J, Wang ZM, Liu Z. Spintronics in Two-Dimensional Materials. NANO-MICRO LETTERS 2020; 12:93. [PMID: 34138100 PMCID: PMC7770708 DOI: 10.1007/s40820-020-00424-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 03/18/2020] [Indexed: 05/30/2023]
Abstract
Spintronics, exploiting the spin degree of electrons as the information vector, is an attractive field for implementing the beyond Complemetary metal-oxide-semiconductor (CMOS) devices. Recently, two-dimensional (2D) materials have been drawing tremendous attention in spintronics owing to their distinctive spin-dependent properties, such as the ultra-long spin relaxation time of graphene and the spin-valley locking of transition metal dichalcogenides. Moreover, the related heterostructures provide an unprecedented probability of combining the different characteristics via proximity effect, which could remedy the limitation of individual 2D materials. Hence, the proximity engineering has been growing extremely fast and has made significant achievements in the spin injection and manipulation. Nevertheless, there are still challenges toward practical application; for example, the mechanism of spin relaxation in 2D materials is unclear, and the high-efficiency spin gating is not yet achieved. In this review, we focus on 2D materials and related heterostructures to systematically summarize the progress of the spin injection, transport, manipulation, and application for information storage and processing. We also highlight the current challenges and future perspectives on the studies of spintronic devices based on 2D materials.
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Affiliation(s)
- Yanping Liu
- School of Physics and Electronics, Hunan Key Laboratory for Super-Microstructure and Ultrafast Process, Central South University, 932 South Lushan Road, Changsha, 410083, Hunan, People's Republic of China.
- Shenzhen Research Institute of Central South University, A510a, Virtual University Building, Southern District, High-Tech Industrial Park, Yuehai Street, Nanshan District, Shenzhen, People's Republic of China.
- State Key Laboratory of High-Performance Complex Manufacturing, Central South University, 932 South Lushan Road, Changsha, 410083, Hunan, People's Republic of China.
| | - Cheng Zeng
- School of Physics and Electronics, Hunan Key Laboratory for Super-Microstructure and Ultrafast Process, Central South University, 932 South Lushan Road, Changsha, 410083, Hunan, People's Republic of China
| | - Jiahong Zhong
- School of Physics and Electronics, Hunan Key Laboratory for Super-Microstructure and Ultrafast Process, Central South University, 932 South Lushan Road, Changsha, 410083, Hunan, People's Republic of China
| | - Junnan Ding
- School of Physics and Electronics, Hunan Key Laboratory for Super-Microstructure and Ultrafast Process, Central South University, 932 South Lushan Road, Changsha, 410083, Hunan, People's Republic of China
| | - Zhiming M Wang
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, 610054, People's Republic of China.
| | - Zongwen Liu
- School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, NSW, 2006, Australia.
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25
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Computational Atomistic Modeling in Carbon Flatland and Other 2D Nanomaterials. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10051724] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
As in many countries, the rise of nanosciences in Belgium has been triggered in the eighties in the one hand, by the development of scanning tunneling and atomic force microscopes offering an unprecedented possibility to visualize and manipulate the atoms, and in the other hand, by the synthesis of nano-objects in particular carbon nanostructures such as fullerene and nanotubes. Concomitantly, the increasing calculating power and the emergence of computing facilities together with the development of DFT-based ab initio softwares have brought to nanosciences field powerful simulation tools to analyse and predict properties of nano-objects. Starting with 0D and 1D nanostructures, the floor is now occupied by the 2D materials with graphene being the bow of this 2D ship. In this review article, some specific examples of 2D systems has been chosen to illustrate how not only density functional theory (DFT) but also tight-binding (TB) techniques can be daily used to investigate theoretically the electronic, phononic, magnetic, and transport properties of these atomically thin layered materials.
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26
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Zatko V, Galbiati M, Dubois SMM, Och M, Palczynski P, Mattevi C, Brus P, Bezencenet O, Martin MB, Servet B, Charlier JC, Godel F, Vecchiola A, Bouzehouane K, Collin S, Petroff F, Dlubak B, Seneor P. Band-Structure Spin-Filtering in Vertical Spin Valves Based on Chemical Vapor Deposited WS 2. ACS NANO 2019; 13:14468-14476. [PMID: 31774276 DOI: 10.1021/acsnano.9b08178] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We report on spin transport in WS2-based 2D-magnetic tunnel junctions (2D-MTJs), unveiling a band structure spin filtering effect specific to the transition metal dichalcogenides (TMDCs) family. WS2 mono-, bi-, and trilayers are derived by a chemical vapor deposition process and further characterized by Raman spectroscopy, atomic force microscopy (AFM), and photoluminescence spectroscopy. The WS2 layers are then integrated in complete Co/Al2O3/WS2/Co MTJ hybrid spin-valve structures. We make use of a tunnel Co/Al2O3 spin analyzer to probe the extracted spin-polarized current from the WS2/Co interface and its evolution as a function of WS2 layer thicknesses. For monolayer WS2, our technological approach enables the extraction of the largest spin signal reported for a TMDC-based spin valve, corresponding to a spin polarization of PCo/WS2 = 12%. Interestingly, for bi- and trilayer WS2, the spin signal is reversed, which indicates a switch in the mechanism of interfacial spin extraction. With the support of ab initio calculations, we propose a model to address the experimentally measured inversion of the spin polarization based on the change in the WS2 band structure while going from monolayer (direct bandgap) to bilayer (indirect bandgap). These experiments illustrate the rich potential of the families of semiconducting 2D materials for the control of spin currents in 2D-MTJs.
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Affiliation(s)
- Victor Zatko
- Unité Mixte de Physique, CNRS, Thales , Univ Paris-Sud, Université Paris-Saclay , 91767 Palaiseau , France
| | - Marta Galbiati
- Unité Mixte de Physique, CNRS, Thales , Univ Paris-Sud, Université Paris-Saclay , 91767 Palaiseau , France
| | - Simon Mutien-Marie Dubois
- Unité Mixte de Physique, CNRS, Thales , Univ Paris-Sud, Université Paris-Saclay , 91767 Palaiseau , France
- Institute of Condensed Matter and Nanosciences , Université catholique de Louvain , B-1348 Louvain-la-Neuve , Belgium
| | - Mauro Och
- Department of Materials , Imperial College London , Exhibition Road , London SW7 2AZ , U.K
| | - Pawel Palczynski
- Department of Materials , Imperial College London , Exhibition Road , London SW7 2AZ , U.K
| | - Cecilia Mattevi
- Department of Materials , Imperial College London , Exhibition Road , London SW7 2AZ , U.K
| | - Pierre Brus
- Unité Mixte de Physique, CNRS, Thales , Univ Paris-Sud, Université Paris-Saclay , 91767 Palaiseau , France
- Thales Research and Technology , 1 avenue Augustin Fresnel , 91767 Palaiseau , France
| | - Odile Bezencenet
- Thales Research and Technology , 1 avenue Augustin Fresnel , 91767 Palaiseau , France
| | - Marie-Blandine Martin
- Unité Mixte de Physique, CNRS, Thales , Univ Paris-Sud, Université Paris-Saclay , 91767 Palaiseau , France
| | - Bernard Servet
- Thales Research and Technology , 1 avenue Augustin Fresnel , 91767 Palaiseau , France
| | - Jean-Christophe Charlier
- Institute of Condensed Matter and Nanosciences , Université catholique de Louvain , B-1348 Louvain-la-Neuve , Belgium
| | - Florian Godel
- Unité Mixte de Physique, CNRS, Thales , Univ Paris-Sud, Université Paris-Saclay , 91767 Palaiseau , France
| | - Aymeric Vecchiola
- Unité Mixte de Physique, CNRS, Thales , Univ Paris-Sud, Université Paris-Saclay , 91767 Palaiseau , France
| | - Karim Bouzehouane
- Unité Mixte de Physique, CNRS, Thales , Univ Paris-Sud, Université Paris-Saclay , 91767 Palaiseau , France
| | - Sophie Collin
- Unité Mixte de Physique, CNRS, Thales , Univ Paris-Sud, Université Paris-Saclay , 91767 Palaiseau , France
| | - Frédéric Petroff
- Unité Mixte de Physique, CNRS, Thales , Univ Paris-Sud, Université Paris-Saclay , 91767 Palaiseau , France
| | - Bruno Dlubak
- Unité Mixte de Physique, CNRS, Thales , Univ Paris-Sud, Université Paris-Saclay , 91767 Palaiseau , France
| | - Pierre Seneor
- Unité Mixte de Physique, CNRS, Thales , Univ Paris-Sud, Université Paris-Saclay , 91767 Palaiseau , France
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27
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Cuadrado R, Pruneda M. Guidelines for Selecting Interlayer Spacers in Synthetic 2D-Based Antiferromagnets from First-Principles Simulations. NANOMATERIALS (BASEL, SWITZERLAND) 2019; 9:E1764. [PMID: 31835819 PMCID: PMC6955936 DOI: 10.3390/nano9121764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 12/05/2019] [Accepted: 12/06/2019] [Indexed: 06/10/2023]
Abstract
Following the recent synthesis of graphene-based antiferromagnetic ultrathin heterostructures made of Co and Fe, we analyse the effect of the spacer between both ferromagnetic materials. Using density functional calculations, we carried out an exhaustive study of the geometric, electronic and magnetic properties for intercalated single Co MLs on top of Ir(111) coupled to monolayered Fe through n graphene layers (n = 1, 2, 3) or monolayered h-BN. Different local atomic arrangements have been considered to model the Moiré patterns expected in these heterostructures. The magnetic exchange interactions between both ferromagnets ( J C o - F e ) are computed from explicit calculations of parallel and anti-parallel Fe/Co inter-layer alignments, and discussed in the context of recent experiments. Our analysis confirms that the robust antiferromagnetic superexchange-coupling between Fe and Co layers is mediated by the graphene spacer through the hybridization of C's p z orbitals with Fe and Co's 3d states. The hybridization is substantially suppressed for multilayered graphene spacers, for which the magnetic coupling between ferromagnets is critically reduced, suggesting the need for ultrathin (monolayer) spacers in the design of synthetic graphene-based antiferromagnets. In the case of h-BN, p z orbitals also mediate d(Fe/Co) coupling. However, there is a larger contribution of local ferromagnetic interactions. Magnetic anisotropy energies were also calculated using a fully relativistic description, and show out-of-plane easy axis for all the configurations, with remarkable net values in the range from 1 to 4 meV.
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Affiliation(s)
- Ramón Cuadrado
- Catalan Institute of Nanoscience and Nanotechnology - ICN2, CSIC and BIST, Campus UAB, 08193 Bellaterra, Spain
- Universitat Autonoma de Barcelona, 08193 Bellaterra (Cerdanyola del Valles), Spain
| | - Miguel Pruneda
- Catalan Institute of Nanoscience and Nanotechnology - ICN2, CSIC and BIST, Campus UAB, 08193 Bellaterra, Spain
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28
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Luo Y, Xie Y, Ye X, Wang Y. A self-powered phosphorene photodetector with excellent spin-filtering and spin-valve effects. Phys Chem Chem Phys 2019; 21:7613-7617. [PMID: 30906937 DOI: 10.1039/c9cp00943d] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Spin-filtering and spin-valve effects are fundamental issues of spintronics in two-dimensional materials, where a self-powered nanotechnology is also highly desired for low-power consumption. Herein, we report a self-powered nickel-phosphorene-nickel photodetector driven by photogalvanic effects (PGEs), based on quantum transport simulations. Persistent photocurrent is generated at zero bias due to PGEs induced by vertical illumination with linearly and elliptically polarized light. Moreover, fully spin-polarized photocurrent and large magnetoresistance can be obtained by tunneling the photon energy and light polarization, which indicates both excellent spin-filtering and spin-valve effects. These results suggest a promising application of PGE-driven phosphorene photodetectors in low energy-consumption spintronic devices.
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Affiliation(s)
- Yongzhi Luo
- Department of Physics, Shanghai Normal University, 100 Guilin Road, Shanghai 200232, P. R. China.
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29
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Wang R, Purdie DG, Fan Y, Massabuau FCP, Braeuninger-Weimer P, Burton OJ, Blume R, Schloegl R, Lombardo A, Weatherup RS, Hofmann S. A Peeling Approach for Integrated Manufacturing of Large Monolayer h-BN Crystals. ACS NANO 2019; 13:2114-2126. [PMID: 30642169 DOI: 10.1021/acsnano.8b08712] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Hexagonal boron nitride (h-BN) is the only known material aside from graphite with a structure composed of simple, stable, noncorrugated atomically thin layers. While historically used as a lubricant in powder form, h-BN layers have become particularly attractive as an ultimately thin insulator, barrier, or encapsulant. Practically all emerging electronic and photonic device concepts currently rely on h-BN exfoliated from small bulk crystallites, which limits device dimensions and process scalability. We here focus on a systematic understanding of Pt-catalyzed h-BN crystal formation, in order to address this integration challenge for monolayer h-BN via an integrated chemical vapor deposition (CVD) process that enables h-BN crystal domain sizes exceeding 0.5 mm and a merged, continuous layer in a growth time of less than 45 min. The process makes use of commercial, reusable Pt foils and allows a delamination process for easy and clean h-BN layer transfer. We demonstrate sequential pick-up for the assembly of graphene/h-BN heterostructures with atomic layer precision, while minimizing interfacial contamination. The approach can be readily combined with other layered materials and enables the integration of CVD h-BN into high-quality, reliable 2D material device layer stacks.
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Affiliation(s)
- Ruizhi Wang
- Department of Engineering , University of Cambridge , 9 JJ Thomson Avenue , Cambridge CB3 0FA , United Kingdom
| | - David G Purdie
- Department of Engineering , University of Cambridge , 9 JJ Thomson Avenue , Cambridge CB3 0FA , United Kingdom
- Cambridge Graphene Centre , University of Cambridge , 9 JJ Thomson Avenue , Cambridge CB3 0FA , United Kingdom
| | - Ye Fan
- Department of Engineering , University of Cambridge , 9 JJ Thomson Avenue , Cambridge CB3 0FA , United Kingdom
| | - Fabien C-P Massabuau
- Department of Materials Science and Metallurgy , University of Cambridge , 27 Charles Babbage Road , Cambridge CB3 0FA , United Kingdom
| | - Philipp Braeuninger-Weimer
- Department of Engineering , University of Cambridge , 9 JJ Thomson Avenue , Cambridge CB3 0FA , United Kingdom
| | - Oliver J Burton
- Department of Engineering , University of Cambridge , 9 JJ Thomson Avenue , Cambridge CB3 0FA , United Kingdom
| | - Raoul Blume
- Helmholtz-Zentrum Berlin für Materialen und Energie , D-12489 Berlin , Germany
| | | | - Antonio Lombardo
- Department of Engineering , University of Cambridge , 9 JJ Thomson Avenue , Cambridge CB3 0FA , United Kingdom
- Cambridge Graphene Centre , University of Cambridge , 9 JJ Thomson Avenue , Cambridge CB3 0FA , United Kingdom
| | - Robert S Weatherup
- School of Chemistry , University of Manchester , Oxford Road , Manchester M13 9PL , U.K
- University of Manchester at Harwell, Diamond Light Source , Didcot , Oxfordshire OX11 0DE , U.K
| | - Stephan Hofmann
- Department of Engineering , University of Cambridge , 9 JJ Thomson Avenue , Cambridge CB3 0FA , United Kingdom
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Wang X, Hossain M, Wei Z, Xie L. Growth of two-dimensional materials on hexagonal boron nitride (h-BN). NANOTECHNOLOGY 2019; 30:034003. [PMID: 30444726 DOI: 10.1088/1361-6528/aaeb70] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
With its atomically smooth surface yet no dangling bond, chemical inertness and high temperature sustainability, the insulating hexagonal boron nitride (h-BN) can be an ideal substrate for two-dimensional (2D) material growth and device measurement. In this review, research progress on the chemical growth of 2D materials on h-BN has been summarized, such as chemical vapor deposition and molecular beam epitaxy of graphene and various transition metal dichalcogenides. Further, stacking of the as-grown 2D materials relative to h-BN, thermal expansion matching between the deposited materials and h-BN, electrical property of 2D materials on h-BN have been discussed in detail.
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Affiliation(s)
- Xinsheng Wang
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
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