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Wu R, Zhang H, Ma H, Zhao B, Li W, Chen Y, Liu J, Liang J, Qin Q, Qi W, Chen L, Li J, Li B, Duan X. Synthesis, Modulation, and Application of Two-Dimensional TMD Heterostructures. Chem Rev 2024; 124:10112-10191. [PMID: 39189449 DOI: 10.1021/acs.chemrev.4c00174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/28/2024]
Abstract
Two-dimensional (2D) transition metal dichalcogenide (TMD) heterostructures have attracted a lot of attention due to their rich material diversity and stack geometry, precise controllability of structure and properties, and potential practical applications. These heterostructures not only overcome the inherent limitations of individual materials but also enable the realization of new properties through appropriate combinations, establishing a platform to explore new physical and chemical properties at micro-nano-pico scales. In this review, we systematically summarize the latest research progress in the synthesis, modulation, and application of 2D TMD heterostructures. We first introduce the latest techniques for fabricating 2D TMD heterostructures, examining the rationale, mechanisms, advantages, and disadvantages of each strategy. Furthermore, we emphasize the importance of characteristic modulation in 2D TMD heterostructures and discuss some approaches to achieve novel functionalities. Then, we summarize the representative applications of 2D TMD heterostructures. Finally, we highlight the challenges and future perspectives in the synthesis and device fabrication of 2D TMD heterostructures and provide some feasible solutions.
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Affiliation(s)
- Ruixia Wu
- Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, Changsha 410082, China
- Hunan Provincial Key Laboratory of Two-Dimensional Materials, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Hongmei Zhang
- Hunan Provincial Key Laboratory of Two-Dimensional Materials, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Huifang Ma
- Innovation Center for Gallium Oxide Semiconductor (IC-GAO), National and Local Joint Engineering Laboratory for RF Integration and Micro-Assembly Technologies, College of Integrated Circuit Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
- School of Flexible Electronics (Future Technologies) Institute of Advanced Materials, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, Nanjing 211816, China
| | - Bei Zhao
- School of Physics and Key Laboratory of Quantum Materials and Devices of Ministry of Education, Southeast University, Nanjing 211189, China
| | - Wei Li
- Hunan Provincial Key Laboratory of Two-Dimensional Materials, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Yang Chen
- Hunan Provincial Key Laboratory of Two-Dimensional Materials, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Jianteng Liu
- Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Jingyi Liang
- Hunan Provincial Key Laboratory of Two-Dimensional Materials, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Qiuyin Qin
- Hunan Provincial Key Laboratory of Two-Dimensional Materials, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Weixu Qi
- Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Liang Chen
- Hunan Provincial Key Laboratory of Two-Dimensional Materials, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Jia Li
- Hunan Provincial Key Laboratory of Two-Dimensional Materials, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Bo Li
- Changsha Semiconductor Technology and Application Innovation Research Institute, School of Physics and Electronics, College of Semiconductors (College of Integrated Circuits), Hunan University, Changsha 410082, China
| | - Xidong Duan
- Hunan Provincial Key Laboratory of Two-Dimensional Materials, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
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2
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Wang F, Shi G, Kim KW, Park HJ, Jang JG, Tan HR, Lin M, Liu Y, Kim T, Yang D, Zhao S, Lee K, Yang S, Soumyanarayanan A, Lee KJ, Yang H. Field-free switching of perpendicular magnetization by two-dimensional PtTe 2/WTe 2 van der Waals heterostructures with high spin Hall conductivity. NATURE MATERIALS 2024; 23:768-774. [PMID: 38243113 DOI: 10.1038/s41563-023-01774-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 11/28/2023] [Indexed: 01/21/2024]
Abstract
The key challenge of spin-orbit torque applications lies in exploring an excellent spin source capable of generating out-of-plane spins while exhibiting high spin Hall conductivity. Here we combine PtTe2 for high spin conductivity and WTe2 for low crystal symmetry to satisfy the above requirements. The PtTe2/WTe2 bilayers exhibit a high in-plane spin Hall conductivity σs,y ≈ 2.32 × 105 × ħ/2e Ω-1 m-1 and out-of-plane spin Hall conductivity σs,z ≈ 0.25 × 105 × ħ/2e Ω-1 m-1, where ħ is the reduced Planck's constant and e is the value of the elementary charge. The out-of-plane spins in PtTe2/WTe2 bilayers enable the deterministic switching of perpendicular magnetization at room temperature without magnetic fields, and the power consumption is 67 times smaller than that of the Pt control case. The high out-of-plane spin Hall conductivity is attributed to the conversion from in-plane spin to out-of-plane spin, induced by the crystal asymmetry of WTe2. Our work establishes a low-power perpendicular magnetization manipulation based on wafer-scale two-dimensional van der Waals heterostructures.
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Affiliation(s)
- Fei Wang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Guoyi Shi
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
- Integrative Sciences and Engineering Programme, NUS Graduate School, National University of Singapore, Singapore, Singapore
| | - Kyoung-Whan Kim
- Center of Spintronics, Korea Institute of Science and Technology, Seoul, Korea
| | - Hyeon-Jong Park
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, Korea
| | - Jae Gwang Jang
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
| | - Hui Ru Tan
- Institute of Materials Research & Engineering, Agency for Science Technology & Research (A*STAR), Singapore, Singapore
| | - Ming Lin
- Institute of Materials Research & Engineering, Agency for Science Technology & Research (A*STAR), Singapore, Singapore
| | - Yakun Liu
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Taeheon Kim
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Dongsheng Yang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Shishun Zhao
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Kyusup Lee
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Shuhan Yang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Anjan Soumyanarayanan
- Institute of Materials Research & Engineering, Agency for Science Technology & Research (A*STAR), Singapore, Singapore
- Department of Physics, National University of Singapore, Singapore, Singapore
| | - Kyung-Jin Lee
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea.
| | - Hyunsoo Yang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore.
- Integrative Sciences and Engineering Programme, NUS Graduate School, National University of Singapore, Singapore, Singapore.
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3
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Bainsla L, Zhao B, Behera N, Hoque AM, Sjöström L, Martinelli A, Abdel-Hafiez M, Åkerman J, Dash SP. Large out-of-plane spin-orbit torque in topological Weyl semimetal TaIrTe 4. Nat Commun 2024; 15:4649. [PMID: 38821948 PMCID: PMC11143358 DOI: 10.1038/s41467-024-48872-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Accepted: 05/16/2024] [Indexed: 06/02/2024] Open
Abstract
The unique electronic properties of topological quantum materials, such as protected surface states and exotic quasiparticles, can provide an out-of-plane spin-polarized current needed for external field-free magnetization switching of magnets with perpendicular magnetic anisotropy. Conventional spin-orbit torque (SOT) materials provide only an in-plane spin-polarized current, and recently explored materials with lower crystal symmetries provide very low out-of-plane spin-polarized current components, which are not suitable for energy-efficient SOT applications. Here, we demonstrate a large out-of-plane damping-like SOT at room temperature using the topological Weyl semimetal candidate TaIrTe4 with a lower crystal symmetry. We performed spin-torque ferromagnetic resonance (STFMR) and second harmonic Hall measurements on devices based on TaIrTe4/Ni80Fe20 heterostructures and observed a large out-of-plane damping-like SOT efficiency. The out-of-plane spin Hall conductivity is estimated to be (4.05 ± 0.23)×104 (ℏ ⁄ 2e) (Ωm)-1, which is an order of magnitude higher than the reported values in other materials.
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Affiliation(s)
- Lakhan Bainsla
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296, Göteborg, Sweden.
- Department of Physics, Indian Institute of Technology Ropar, Rupnagar, 140001, Punjab, India.
| | - Bing Zhao
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296, Göteborg, Sweden
| | - Nilamani Behera
- Department of Physics, University of Gothenburg, Göteborg, SE-41296, Göteborg, Sweden
| | - Anamul Md Hoque
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296, Göteborg, Sweden
| | - Lars Sjöström
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296, Göteborg, Sweden
| | - Anna Martinelli
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Göteborg, 41296, Sweden
| | - Mahmoud Abdel-Hafiez
- Department of Applied Physics and Astronomy, University of Sharjah, P. O. Box 27272, Sharjah, United Arab Emirates
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20, Uppsala, Sweden
| | - Johan Åkerman
- Department of Physics, University of Gothenburg, Göteborg, SE-41296, Göteborg, Sweden
- Center for Science and Innovation in Spintronics, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
- Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
| | - Saroj P Dash
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296, Göteborg, Sweden.
- Wallenberg Initiative Materials Science for Sustainability, Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296, Göteborg, Sweden.
- Graphene Center, Chalmers University of Technology, SE-41296, Göteborg, Sweden.
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Cao L, Chen Q, Zhu Y, Tong K, Li W, Ma J, Jalali M, Huang Z, Wu J, Zhai Y. Interfacial Modulation of Spin-Orbit Torques Induced by Two-Dimensional van der Waals Material ZrSe 3. ACS APPLIED MATERIALS & INTERFACES 2024; 16:19764-19770. [PMID: 38577833 DOI: 10.1021/acsami.4c00881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/06/2024]
Abstract
Two-dimensional van der Waals (2D vdW) materials are widely used in spin-orbit torque (SOT) devices. Recent studies have demonstrated the low crystal symmetry and large spin Hall conductivity of 2D vdW ZrSe3, indicating its potential applications in low-power SOT devices. Here, we study the interfacial contribution of SOTs and current-induced magnetization switching in the ZrSe3/Py (Ni80Fe20) and ZrSe3/Cu/Py heterostructures. SOT efficiencies of samples are detected by the spin-torque ferromagnetic resonance (ST-FMR), and out-of-plane damping-like torque (τB) is observed. The ratio between τB and the field-like torque (τA) decreases from 0.175 to 0.138 when inserting 1 nm Cu at the interface and then drops to 0.001 when the thickness of Cu intercalation is 2 nm, indicating that Cu intercalation inhibits the τB component of SOT. Moreover, the SOT efficiency is increased from 3.05 to 5.21, which may be attributed to the Cu intercalation being beneficial to improve the interface between Py and ZrSe3. Theoretical calculation has shown that the Cu spacer can change the conductivity of ZrSe3 from semiconductor to conductor, thereby decreasing the Schottky barrier and increasing the transmission efficiency of the spin current. Furthermore, magneto-optical Kerr effect (MOKE) microscopy is employed to verify the current-driven magnetization switching in these structures. In comparison to the ZrSe3/Py bilayer, the critical current density of ZrSe3/Cu/Py is reduced when inserting 1 nm Cu, demonstrating the higher SOT efficiency and lower power consumption in ZrSe3/Cu/Py structures.
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Affiliation(s)
- Lulu Cao
- Key Laboratory of Quantum Materials and Devices of Ministry of Education, School of Physics, Southeast University, Nanjing, Jiangsu 211189, People's Republic of China
| | - Qian Chen
- Key Laboratory of Quantum Materials and Devices of Ministry of Education, School of Physics, Southeast University, Nanjing, Jiangsu 211189, People's Republic of China
| | - Yonghui Zhu
- Key Laboratory of Quantum Materials and Devices of Ministry of Education, School of Physics, Southeast University, Nanjing, Jiangsu 211189, People's Republic of China
| | - Kaiyu Tong
- Department of Physics, Engineering and Technology, University of York, York YO10 5DD, United Kingdom
| | - Wenjia Li
- Department of Physics, Engineering and Technology, University of York, York YO10 5DD, United Kingdom
| | - Jun Ma
- Department of Physics, Engineering and Technology, University of York, York YO10 5DD, United Kingdom
| | - Milad Jalali
- Key Laboratory of Quantum Materials and Devices of Ministry of Education, School of Physics, Southeast University, Nanjing, Jiangsu 211189, People's Republic of China
| | - Zhaocong Huang
- Key Laboratory of Quantum Materials and Devices of Ministry of Education, School of Physics, Southeast University, Nanjing, Jiangsu 211189, People's Republic of China
| | - Jing Wu
- Department of Physics, Engineering and Technology, University of York, York YO10 5DD, United Kingdom
| | - Ya Zhai
- Key Laboratory of Quantum Materials and Devices of Ministry of Education, School of Physics, Southeast University, Nanjing, Jiangsu 211189, People's Republic of China
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Abdukayumov K, Mičica M, Ibrahim F, Vojáček L, Vergnaud C, Marty A, Veuillen JY, Mallet P, de Moraes IG, Dosenovic D, Gambarelli S, Maurel V, Wright A, Tignon J, Mangeney J, Ouerghi A, Renard V, Mesple F, Li J, Bonell F, Okuno H, Chshiev M, George JM, Jaffrès H, Dhillon S, Jamet M. Atomic-Layer Controlled Transition from Inverse Rashba-Edelstein Effect to Inverse Spin Hall Effect in 2D PtSe 2 Probed by THz Spintronic Emission. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2304243. [PMID: 38160244 DOI: 10.1002/adma.202304243] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Revised: 11/09/2023] [Indexed: 01/03/2024]
Abstract
2D materials, such as transition metal dichalcogenides, are ideal platforms for spin-to-charge conversion (SCC) as they possess strong spin-orbit coupling (SOC), reduced dimensionality and crystal symmetries as well as tuneable band structure, compared to metallic structures. Moreover, SCC can be tuned with the number of layers, electric field, or strain. Here, SCC in epitaxially grown 2D PtSe2 by THz spintronic emission is studied since its 1T crystal symmetry and strong SOC favor SCC. High quality of as-grown PtSe2 layers is demonstrated, followed by in situ ferromagnet deposition by sputtering that leaves the PtSe2 unaffected, resulting in well-defined clean interfaces as evidenced with extensive characterization. Through this atomic growth control and using THz spintronic emission, the unique thickness-dependent electronic structure of PtSe2 allows the control of SCC. Indeed, the transition from the inverse Rashba-Edelstein effect (IREE) in 1-3 monolayers (ML) to the inverse spin Hall effect (ISHE) in multilayers (>3 ML) of PtSe2 enabling the extraction of the perpendicular spin diffusion length and relative strength of IREE and ISHE is demonstrated. This band structure flexibility makes PtSe2 an ideal candidate to explore the underlying mechanisms and engineering of the SCC as well as for the development of tuneable THz spintronic emitters.
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Affiliation(s)
- Khasan Abdukayumov
- CEA, CNRS, Université Grenoble Alpes, Grenoble INP, IRIG-Spintec, Grenoble, 38000, France
| | - Martin Mičica
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, Paris, 75005, France
| | - Fatima Ibrahim
- CEA, CNRS, Université Grenoble Alpes, Grenoble INP, IRIG-Spintec, Grenoble, 38000, France
| | - Libor Vojáček
- CEA, CNRS, Université Grenoble Alpes, Grenoble INP, IRIG-Spintec, Grenoble, 38000, France
| | - Céline Vergnaud
- CEA, CNRS, Université Grenoble Alpes, Grenoble INP, IRIG-Spintec, Grenoble, 38000, France
| | - Alain Marty
- CEA, CNRS, Université Grenoble Alpes, Grenoble INP, IRIG-Spintec, Grenoble, 38000, France
| | - Jean-Yves Veuillen
- CNRS, Université Grenoble Alpes, Grenoble INP-UGA, Institut NéeL, Grenoble, 38000, France
| | - Pierre Mallet
- CNRS, Université Grenoble Alpes, Grenoble INP-UGA, Institut NéeL, Grenoble, 38000, France
| | | | | | - Serge Gambarelli
- CEA, CNRS, IRIG-SYMMES, Université Grenoble Alpes, Grenoble, 38000, France
| | - Vincent Maurel
- CEA, CNRS, IRIG-SYMMES, Université Grenoble Alpes, Grenoble, 38000, France
| | - Adrien Wright
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, Paris, 75005, France
| | - Jérôme Tignon
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, Paris, 75005, France
| | - Juliette Mangeney
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, Paris, 75005, France
| | - Abdelkarim Ouerghi
- CNRS, Centre de Nanosciences et de Nanotechnologies, Université Paris-Saclay, Palaiseau, 91120, France
| | - Vincent Renard
- CEA, IRIG-Pheliqs, Université Grenoble Alpes, Grenoble, 38000, France
| | - Florie Mesple
- CEA, IRIG-Pheliqs, Université Grenoble Alpes, Grenoble, 38000, France
| | - Jing Li
- CEA, Leti, Université Grenoble Alpes, Grenoble, 38000, France
| | - Frédéric Bonell
- CEA, CNRS, Université Grenoble Alpes, Grenoble INP, IRIG-Spintec, Grenoble, 38000, France
| | - Hanako Okuno
- CEA, IRIG-MEM, Université Grenoble Alpes, Grenoble, 38000, France
| | - Mairbek Chshiev
- CEA, CNRS, Université Grenoble Alpes, Grenoble INP, IRIG-Spintec, Grenoble, 38000, France
- Institut Universitaire de France, Paris, 75231, France
| | - Jean-Marie George
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, Palaiseau, F-91767, France
| | - Henri Jaffrès
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, Palaiseau, F-91767, France
| | - Sukhdeep Dhillon
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, Paris, 75005, France
| | - Matthieu Jamet
- CEA, CNRS, Université Grenoble Alpes, Grenoble INP, IRIG-Spintec, Grenoble, 38000, France
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Zhang Y, Xu H, Jia K, Lan G, Huang Z, He B, He C, Shao Q, Wang Y, Zhao M, Ma T, Dong J, Guo C, Cheng C, Feng J, Wan C, Wei H, Shi Y, Zhang G, Han X, Yu G. Room temperature field-free switching of perpendicular magnetization through spin-orbit torque originating from low-symmetry type II Weyl semimetal. SCIENCE ADVANCES 2023; 9:eadg9819. [PMID: 37910619 PMCID: PMC10619928 DOI: 10.1126/sciadv.adg9819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 09/28/2023] [Indexed: 11/03/2023]
Abstract
Spin-orbit torque (SOT) is a promising strategy to deterministically switch the perpendicular magnetization, but usually requires an in-plane magnetic field for breaking the mirror symmetry, which is not suitable for most advanced industrial applications. Van der Waals (vdW) materials with low crystalline symmetry and topological band structures, e.g., Weyl semimetals (WSMs), potentially serve as an outstanding system that may simultaneously realize field-free switching and high energy efficiency. Yet, the demonstration of these superiorities at room temperature has not been realized. Here, we achieve a field-free switching of perpendicular magnetization by using a layered type II WSM, TaIrTe4, in a TaIrTe4/Ti/CoFeB system at room temperature with the critical switching current density ~2.4 × 106 A cm-2. The field-free switching is ascribed to the out-of-plane SOT allowed by the low crystal symmetry. Our work suggests that using low-symmetry materials to generate SOT is a promising route for the manipulation of perpendicular magnetization at room temperature.
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Affiliation(s)
- Yu Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hongjun Xu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Ke Jia
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guibin Lan
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhiheng Huang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Bin He
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Congli He
- Institute of Advanced Materials, Beijing Normal University, Beijing 100875, China
| | - Qiming Shao
- Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Yizhan Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Mingkun Zhao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tianyi Ma
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jing Dong
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chenyang Guo
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chen Cheng
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jiafeng Feng
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Caihua Wan
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Hongxiang Wei
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Youguo Shi
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Guangyu Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Xiufeng Han
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Guoqiang Yu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
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7
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Cao C, Chen S, Xiao RC, Zhu Z, Yu G, Wang Y, Qiu X, Liu L, Zhao T, Shao DF, Xu Y, Chen J, Zhan Q. Anomalous spin current anisotropy in a noncollinear antiferromagnet. Nat Commun 2023; 14:5873. [PMID: 37735469 PMCID: PMC10514083 DOI: 10.1038/s41467-023-41568-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 09/09/2023] [Indexed: 09/23/2023] Open
Abstract
Cubic materials host high crystal symmetry and hence are not expected to support anisotropy in transport phenomena. In contrast to this common expectation, here we report an anomalous anisotropy of spin current can emerge in the (001) film of Mn3Pt, a noncollinear antiferromagnetic spin source with face-centered cubic structure. Such spin current anisotropy originates from the intertwined time reversal-odd ([Formula: see text]-odd) and time reversal-even ([Formula: see text]-even) spin Hall effects. Based on symmetry analyses and experimental characterizations of the current-induced spin torques in Mn3Pt-based heterostructures, we find that the spin current generated by Mn3Pt (001) exhibits exotic dependences on the current direction for all the spin components, deviating from that in conventional cubic systems. We also demonstrate that such an anisotropic spin current can be used to realize low-power spintronic applications such as the efficient field-free switching of the perpendicular magnetizations.
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Affiliation(s)
- Cuimei Cao
- Key Laboratory of Polar Materials and Devices (MOE), School of Physics and Electronic Science, East China Normal University, Shanghai, 200241, People's Republic of China
| | - Shiwei Chen
- School of Physics, Hubei University, Wuhan, 430062, People's Republic of China
- Shanghai Key Laboratory of Special Artificial Microstructure Materials, School of Physics Science and Engineering, Tongji University, Shanghai, 200092, People's Republic of China
| | - Rui-Chun Xiao
- Institute of Physical Science and Information Technology, Anhui University, Hefei, 230601, People's Republic of China
| | - Zengtai Zhu
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, People's Republic of China
- Beijing National Laboratory for Condensed Matter, Physics Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, People's Republic of China
| | - Guoqiang Yu
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, People's Republic of China
- Beijing National Laboratory for Condensed Matter, Physics Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, People's Republic of China
| | - Yangping Wang
- Key Laboratory of Polar Materials and Devices (MOE), School of Physics and Electronic Science, East China Normal University, Shanghai, 200241, People's Republic of China
| | - Xuepeng Qiu
- Shanghai Key Laboratory of Special Artificial Microstructure Materials, School of Physics Science and Engineering, Tongji University, Shanghai, 200092, People's Republic of China
| | - Liang Liu
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China
- Department of Materials Science and Engineering, National University of Singapore, Singapore, Singapore
| | - Tieyang Zhao
- Department of Materials Science and Engineering, National University of Singapore, Singapore, Singapore
| | - Ding-Fu Shao
- Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei, 230031, People's Republic of China.
| | - Yang Xu
- Key Laboratory of Polar Materials and Devices (MOE), School of Physics and Electronic Science, East China Normal University, Shanghai, 200241, People's Republic of China.
| | - Jingsheng Chen
- Department of Materials Science and Engineering, National University of Singapore, Singapore, Singapore.
| | - Qingfeng Zhan
- Key Laboratory of Polar Materials and Devices (MOE), School of Physics and Electronic Science, East China Normal University, Shanghai, 200241, People's Republic of China.
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8
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Patton M, Gurung G, Shao DF, Noh G, Mittelstaedt JA, Mazur M, Kim JW, Ryan PJ, Tsymbal EY, Choi SY, Ralph DC, Rzchowski MS, Nan T, Eom CB. Symmetry Control of Unconventional Spin-Orbit Torques in IrO 2. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2301608. [PMID: 37272785 DOI: 10.1002/adma.202301608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Revised: 05/27/2023] [Indexed: 06/06/2023]
Abstract
Spin-orbit torques generated by a spin current are key to magnetic switching in spintronic applications. The polarization of the spin current dictates the direction of switching required for energy-efficient devices. Conventionally, the polarizations of these spin currents are restricted to be along a certain direction due to the symmetry of the material allowing only for efficient in-plane magnetic switching. Unconventional spin-orbit torques arising from novel spin current polarizations, however, have the potential to switch other magnetization orientations such as perpendicular magnetic anisotropy, which is desired for higher density spintronic-based memory devices. Here, it is demonstrated that low crystalline symmetry is not required for unconventional spin-orbit torques and can be generated in a nonmagnetic high symmetry material, iridium dioxide (IrO2 ), using epitaxial design. It is shown that by reducing the relative crystalline symmetry with respect to the growth direction large unconventional spin currents can be generated and hence spin-orbit torques. Furthermore, the spin polarizations detected in (001), (110), and (111) oriented IrO2 thin films are compared to show which crystal symmetries restrict unconventional spin transport. Understanding and tuning unconventional spin transport generation in high symmetry materials can provide a new route towards energy-efficient magnetic switching in spintronic devices.
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Affiliation(s)
- Michael Patton
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Gautam Gurung
- Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, NE, 68588, USA
| | - Ding-Fu Shao
- Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, NE, 68588, USA
| | - Gahee Noh
- Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang, Gyeongbuk, 37673, Republic of Korea
| | | | | | - Jong-Woo Kim
- X-Ray Science Division, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - Philip J Ryan
- X-Ray Science Division, Argonne National Laboratory, Argonne, IL, 60439, USA
- School of Physical Sciences, Dublin City University, Dublin, 9, Ireland
| | - Evgeny Y Tsymbal
- Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, NE, 68588, USA
| | - Si-Young Choi
- Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang, Gyeongbuk, 37673, Republic of Korea
- Center for Van der Waals Quantum Solids, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
- Semiconductor Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Daniel C Ralph
- Cornell University, Ithaca, NY, 14853, USA
- Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY, 14853, USA
| | - Mark S Rzchowski
- Department of Physics, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Tianxiang Nan
- School of Integrated Circuits and Beijing National Research Center for Information Science and Technology (BNRist), Tsinghua University, Beijing, 100084, China
| | - Chang-Beom Eom
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA
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9
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Hazra BK, Pal B, Jeon JC, Neumann RR, Göbel B, Grover B, Deniz H, Styervoyedov A, Meyerheim H, Mertig I, Yang SH, Parkin SSP. Generation of out-of-plane polarized spin current by spin swapping. Nat Commun 2023; 14:4549. [PMID: 37507398 PMCID: PMC10382594 DOI: 10.1038/s41467-023-39884-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 07/03/2023] [Indexed: 07/30/2023] Open
Abstract
The generation of spin currents and their application to the manipulation of magnetic states is fundamental to spintronics. Of particular interest are chiral antiferromagnets that exhibit properties typical of ferromagnetic materials even though they have negligible magnetization. Here, we report the generation of a robust spin current with both in-plane and out-of-plane spin polarization in epitaxial thin films of the chiral antiferromagnet Mn3Sn in proximity to permalloy thin layers. By employing temperature-dependent spin-torque ferromagnetic resonance, we find that the chiral antiferromagnetic structure of Mn3Sn is responsible for an in-plane polarized spin current that is generated from the interior of the Mn3Sn layer and whose temperature dependence follows that of this layer's antiferromagnetic order. On the other hand, the out-of-plane polarized spin current is unrelated to the chiral antiferromagnetic structure and is instead the result of scattering from the Mn3Sn/permalloy interface. We substantiate the later conclusion by performing studies with several other non-magnetic metals all of which are found to exhibit out-of-plane polarized spin currents arising from the spin swapping effect.
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Affiliation(s)
- Binoy K Hazra
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120, Halle (Saale), Germany
| | - Banabir Pal
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120, Halle (Saale), Germany
| | - Jae-Chun Jeon
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120, Halle (Saale), Germany
| | - Robin R Neumann
- Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06099, Halle (Saale), Germany
| | - Börge Göbel
- Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06099, Halle (Saale), Germany
| | - Bharat Grover
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120, Halle (Saale), Germany
| | - Hakan Deniz
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120, Halle (Saale), Germany
| | - Andriy Styervoyedov
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120, Halle (Saale), Germany
| | - Holger Meyerheim
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120, Halle (Saale), Germany
| | - Ingrid Mertig
- Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06099, Halle (Saale), Germany
| | - See-Hun Yang
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120, Halle (Saale), Germany
| | - Stuart S P Parkin
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120, Halle (Saale), Germany.
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10
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Giant field-like torque by the out-of-plane magnetic spin Hall effect in a topological antiferromagnet. Nat Commun 2021; 12:6491. [PMID: 34795211 PMCID: PMC8602386 DOI: 10.1038/s41467-021-26453-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Accepted: 09/27/2021] [Indexed: 12/03/2022] Open
Abstract
Spin-orbit torques (SOT) enable efficient electrical control of the magnetic state of ferromagnets, ferrimagnets and antiferromagnets. However, the conventional SOT has severe limitation that only in-plane spins accumulate near the surface, whether interpreted as a spin Hall effect (SHE) or as an Edelstein effect. Such a SOT is not suitable for controlling perpendicular magnetization, which would be more beneficial for realizing low-power-consumption memory devices. Here we report the observation of a giant magnetic-field-like SOT in a topological antiferromagnet Mn3Sn, whose direction and size can be tuned by changing the order parameter direction of the antiferromagnet. To understand the magnetic SHE (MSHE)- and the conventional SHE-induced SOTs on an equal footing, we formulate them as interface spin-electric-field responses and analyzed using a macroscopic symmetry analysis and a complementary microscopic quantum kinetic theory. In this framework, the large out-of-plane spin accumulation due to the MSHE has an inter-band origin and is likely to be caused by the large momentum-dependent spin splitting in Mn3Sn. Our work demonstrates the unique potential of antiferromagnetic Weyl semimetals in overcoming the limitations of conventional SOTs and in realizing low-power spintronics devices with new functionalities. Conventional spin-orbit torque (SOT) enables electrical control of in-plane spins, not suitable for perpendicular magnetization. Here, the authors observe a large magnetic-field-like SOT due to a large out-of-plane spin accumulation in topological antiferromagnet Mn3Sn.
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11
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You Y, Bai H, Feng X, Fan X, Han L, Zhou X, Zhou Y, Zhang R, Chen T, Pan F, Song C. Cluster magnetic octupole induced out-of-plane spin polarization in antiperovskite antiferromagnet. Nat Commun 2021; 12:6524. [PMID: 34764284 PMCID: PMC8585975 DOI: 10.1038/s41467-021-26893-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 10/26/2021] [Indexed: 11/09/2022] Open
Abstract
Out-of-plane spin polarization σz has attracted increasing interests of researchers recently, due to its potential in high-density and low-power spintronic devices. Noncollinear antiferromagnet (AFM), which has unique 120° triangular spin configuration, has been discovered to possess σz. However, the physical origin of σz in noncollinear AFM is still not clear, and the external magnetic field-free switching of perpendicular magnetic layer using the corresponding σz has not been reported yet. Here, we use the cluster magnetic octupole in antiperovskite AFM Mn3SnN to demonstrate the generation of σz. σz is induced by the precession of carrier spins when currents flow through the cluster magnetic octupole, which also relies on the direction of the cluster magnetic octupole in conjunction with the applied current. With the aid of σz, current induced spin-orbit torque (SOT) switching of adjacent perpendicular ferromagnet is realized without external magnetic field. Our findings present a new perspective to the generation of out-of-plane spin polarizations via noncollinear AFM spin structure, and provide a potential path to realize ultrafast high-density applications.
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Affiliation(s)
- Yunfeng You
- Key Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
| | - Hua Bai
- Key Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
| | - Xiaoyu Feng
- The Key Lab for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou University, Lanzhou, 730000, China
| | - Xiaolong Fan
- The Key Lab for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou University, Lanzhou, 730000, China
| | - Lei Han
- Key Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
| | - Xiaofeng Zhou
- Key Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
| | - Yongjian Zhou
- Key Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
| | - Ruiqi Zhang
- Key Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
| | - Tongjin Chen
- Key Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
| | - Feng Pan
- Key Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
| | - Cheng Song
- Key Laboratory of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China.
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12
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Chen Q, Liang J, Fang B, Zhu Y, Wang J, Lv W, Lv W, Cai J, Huang Z, Zhai Y, Zhang B, Zeng Z. Proximity effect of a two-dimensional van der Waals magnet Fe 3GeTe 2 on nickel films. NANOSCALE 2021; 13:14688-14693. [PMID: 34533556 DOI: 10.1039/d1nr03342e] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Recent advances in two-dimensional van der Waals (2D vdW) magnets provide new platforms to study their magnetism in reduced dimensions. However, most of the studies performed to date have been limited to low temperatures. Here, we report the proximity effect of a 2D vdW magnet Fe3GeTe2 (FGT) on nickel (Ni) films at room temperature. Ferromagnetic resonance measurements show that FGT can increase the perpendicular magnetic anisotropy (PMA) and magnetic damping of the adjacent Ni film. Such an interfacial effect is observed at room temperature, and becomes more pronounced as the temperature decreases. A similar effect is also achieved in another 2D heterostructure of Cr2Ge2Te6/Ni, implying its universality in a variety of 2D magnetic materials. Our work provides a new approach for utilizing 2D magnets in spintronics at room temperature.
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Affiliation(s)
- Qian Chen
- Key Laboratory of Multifunctional Nanomaterials and Smart Systems, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu, 215123, China.
| | - Jian Liang
- School of Physics, Southeast University, Nanjing, Jiangsu, 211189, China.
| | - Bin Fang
- Nanchang Nano-Devices and Technologies Division, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Nanchang, Jiangxi, 330200, China
| | - Yonghui Zhu
- Key Laboratory of Multifunctional Nanomaterials and Smart Systems, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu, 215123, China.
- School of Physics, Southeast University, Nanjing, Jiangsu, 211189, China.
| | - Jiachen Wang
- Key Laboratory of Multifunctional Nanomaterials and Smart Systems, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu, 215123, China.
| | - Weiming Lv
- Key Laboratory of Multifunctional Nanomaterials and Smart Systems, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu, 215123, China.
- Nanchang Nano-Devices and Technologies Division, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Nanchang, Jiangxi, 330200, China
| | - Wenxing Lv
- Physics Laboratory, Industrial Training Center, Shenzhen Polytechnic, Shenzhen, Guangdong, 518055, China
| | - Jialin Cai
- Key Laboratory of Multifunctional Nanomaterials and Smart Systems, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu, 215123, China.
- Nanchang Nano-Devices and Technologies Division, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Nanchang, Jiangxi, 330200, China
| | - Zhaocong Huang
- School of Physics, Southeast University, Nanjing, Jiangsu, 211189, China.
| | - Ya Zhai
- School of Physics, Southeast University, Nanjing, Jiangsu, 211189, China.
| | - Baoshun Zhang
- Key Laboratory of Multifunctional Nanomaterials and Smart Systems, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu, 215123, China.
| | - Zhongming Zeng
- Key Laboratory of Multifunctional Nanomaterials and Smart Systems, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu, 215123, China.
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13
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Tang W, Liu H, Li Z, Pan A, Zeng Y. Spin-Orbit Torque in Van der Waals-Layered Materials and Heterostructures. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:e2100847. [PMID: 34323390 PMCID: PMC8456225 DOI: 10.1002/advs.202100847] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 06/03/2021] [Indexed: 06/13/2023]
Abstract
Spin-orbit torque (SOT) opens an efficient and versatile avenue for the electrical manipulation of magnetization in spintronic devices. The enhancement of SOT efficiency and reduction of power consumption are key points for the implementation of high-performance SOT devices, which strongly rely on the spin-orbit coupling (SOC) strength and magnetic properties of ferromagnetic/non-magnetic heterostructures. Recently, van der Waals-layered materials have shown appealing properties for use in efficient SOT applications. On the one hand, transition-metal dichalcogenides, topological insulators, and graphene-based heterostructures possess appreciable SOC strength. This feature can efficiently converse the charge current into spin current and result in large SOT. On the other hand, the newly discovered layered magnetic materials provide ultra-thin and gate-tunable ferromagnetic candidates for high-performance SOT devices. In this review, the latest advancements of SOT research in various layered materials are summarized. First, a brief introduction of SOT is given. Second, SOT studies of various layered materials and heterostructures are summarized. Subsequently, progresses on SOT-induced magnetization switching are presented. Finally, current challenges and prospects for future development are suggested.
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Affiliation(s)
- Wei Tang
- Key laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong ProvinceCollege of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhen518060China
| | - Haoliang Liu
- State Key Laboratory on Tunable Laser TechnologyMinistry of Industry and Information Technology Key Lab of Micro‐Nano Optoelectronic Information SystemSchool of ScienceHarbin Institute of TechnologyShenzhen518055China
| | - Zhe Li
- State Key Laboratory on Tunable Laser TechnologyMinistry of Industry and Information Technology Key Lab of Micro‐Nano Optoelectronic Information SystemSchool of ScienceHarbin Institute of TechnologyShenzhen518055China
| | - Anlian Pan
- Key Laboratory for Micro‐Nano Physics and Technology of Hunan ProvinceCollege of Materials Science and EngineeringHunan UniversityChangsha410082China
| | - Yu‐Jia Zeng
- Key laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong ProvinceCollege of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhen518060China
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14
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Tian M, Zhu Y, Jalali M, Jiang W, Liang J, Huang Z, Chen Q, Zeng Z, Zhai Y. Two-Dimensional Van Der Waals Materials for Spin-Orbit Torque Applications. FRONTIERS IN NANOTECHNOLOGY 2021. [DOI: 10.3389/fnano.2021.732916] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Spin-orbit torque (SOT) provides an efficient approach to control the magnetic state and dynamics in different classes of materials. Recent years, the crossover between two-dimensional van der Waals (2D vdW) materials and SOT opens a new prospect to push SOT devices to the 2D limit. In this mini-review, we summarize the latest progress in 2D vdW materials for SOT applications, highlighting the comparison of the performance between devices with various structures. It is prospected that the large family of 2D vdW materials and numerous combinations of heterostructures will widely extend the material choices and bring new opportunities to SOT devices in the future.
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15
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Zhou J, Shu X, Lin W, Shao DF, Chen S, Liu L, Yang P, Tsymbal EY, Chen J. Modulation of Spin-Orbit Torque from SrRuO 3 by Epitaxial-Strain-Induced Octahedral Rotation. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2007114. [PMID: 34145647 DOI: 10.1002/adma.202007114] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 03/30/2021] [Indexed: 06/12/2023]
Abstract
Spin-orbit torque (SOT), which arises from the spin-orbit coupling of conduction electrons, is believed to be the key route for developing low-power, high-speed, and nonvolatile memory devices. Despite the theoretical prediction of pronounced Berry phase curvatures in certain transition-metal perovskite oxides, which lead to considerable intrinsic spin Hall conductivity, SOT from this class of materials has rarely been reported until recently. Here, the SOT generated by epitaxial SrRuO3 of three different crystal structures is systematically studied. The results of both spin-torque ferromagnetic resonance and in-plane harmonic Hall voltage measurements concurrently reveal that the intrinsic SOT efficiency of SrRuO3 decreases when the epitaxial strain changes from tensile to compressive. The X-ray diffraction data demonstrate a strong correlation between the magnitude of SOT and octahedral rotation around the in-plane axes of SrRuO3 , consistent with the theoretical prediction. This work offers new possibilities of tuning SOT with crystal structures and novel opportunities of integrating the unique properties of perovskite oxides with spintronic functionalities.
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Affiliation(s)
- Jing Zhou
- Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore, 117575, Singapore
| | - Xinyu Shu
- Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore, 117575, Singapore
| | - Weinan Lin
- Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore, 117575, Singapore
| | - Ding Fu Shao
- Department of Physics and Astronomy and Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, NE, 68588, USA
| | - Shaohai Chen
- Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore, 117575, Singapore
| | - Liang Liu
- Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore, 117575, Singapore
| | - Ping Yang
- Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore, 117575, Singapore
- Singapore Synchrotron Light Source (SSLS), National University of Singapore, 5 Research Link, Singapore, 117603, Singapore
| | - Evgeny Y Tsymbal
- Department of Physics and Astronomy and Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, NE, 68588, USA
| | - Jingsheng Chen
- Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore, 117575, Singapore
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16
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Peng CW, Liao WB, Chen TY, Pai CF. Efficient Spin-Orbit Torque Generation in Semiconducting WTe 2 with Hopping Transport. ACS APPLIED MATERIALS & INTERFACES 2021; 13:15950-15957. [PMID: 33769782 DOI: 10.1021/acsami.1c03530] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Spin-orbit torques (SOTs) from transition metal dichalcogenide systems (TMDs) in conjunction with ferromagnetic materials are recently found to be attractive in spintronics for their versatile features. However, most of the previously studied crystalline TMDs are prepared by mechanical exfoliation, which limits their potentials for industrial applications. Here, we show that amorphous WTe2 heterostructures deposited by magnetron sputtering possess a sizable damping-like SOT efficiency of ξDLWTe2 ≈ 0.20 and low damping constant of α = 0.009 ± 0.001. Only an extremely low critical switching current density of Jc≈ 7.05 × 109 A/m2 is required to achieve SOT-driven magnetization switching. The SOT efficiency is further proved to depend on the W and Te relative compositions in the co-sputtered W100-xTex samples, from which a sign change of ξDLWTe2 is observed. In addition, the electronic transport in amorphous WTe2 is found to be semiconducting and is governed by a hopping mechanism. With the above advantages and rich tunability, amorphous and semiconducting WTe2 serves as a unique SOT source for future spintronics applications.
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Affiliation(s)
- Cheng-Wei Peng
- Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan
| | - Wei-Bang Liao
- Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan
| | - Tian-Yue Chen
- Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan
| | - Chi-Feng Pai
- Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan
- Center of Atomic Initiative for New Materials, National Taiwan University, Taipei 10617, Taiwan
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17
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Shao Q, Li P, Liu L, Yang H, Fukami S, Razavi A, Wu H, Wang K, Freimuth F, Mokrousov Y, Stiles MD, Emori S, Hoffmann A, Åkerman J, Roy K, Wang JP, Yang SH, Garello K, Zhang W. Roadmap of spin-orbit torques. IEEE TRANSACTIONS ON MAGNETICS 2021; 57:10.48550/arXiv.2104.11459. [PMID: 37057056 PMCID: PMC10091395 DOI: 10.48550/arxiv.2104.11459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Spin-orbit torque (SOT) is an emerging technology that enables the efficient manipulation of spintronic devices. The initial processes of interest in SOTs involved electric fields, spin-orbit coupling, conduction electron spins and magnetization. More recently interest has grown to include a variety of other processes that include phonons, magnons, or heat. Over the past decade, many materials have been explored to achieve a larger SOT efficiency. Recently, holistic design to maximize the performance of SOT devices has extended material research from a nonmagnetic layer to a magnetic layer. The rapid development of SOT has spurred a variety of SOT-based applications. In this Roadmap paper, we first review the theories of SOTs by introducing the various mechanisms thought to generate or control SOTs, such as the spin Hall effect, the Rashba-Edelstein effect, the orbital Hall effect, thermal gradients, magnons, and strain effects. Then, we discuss the materials that enable these effects, including metals, metallic alloys, topological insulators, two-dimensional materials, and complex oxides. We also discuss the important roles in SOT devices of different types of magnetic layers, such as magnetic insulators, antiferromagnets, and ferrimagnets. Afterward, we discuss device applications utilizing SOTs. We discuss and compare three-terminal and two-terminal SOT-magnetoresistive random-access memories (MRAMs); we mention various schemes to eliminate the need for an external field. We provide technological application considerations for SOT-MRAM and give perspectives on SOT-based neuromorphic devices and circuits. In addition to SOT-MRAM, we present SOT-based spintronic terahertz generators, nano-oscillators, and domain wall and skyrmion racetrack memories. This paper aims to achieve a comprehensive review of SOT theory, materials, and applications, guiding future SOT development in both the academic and industrial sectors.
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Affiliation(s)
- Qiming Shao
- Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology
| | - Peng Li
- Department of Electrical and Computer Engineering, Auburn University
| | - Luqiao Liu
- Electrical Engineering and Computer Science, Massachusetts Institute of Technology
| | - Hyunsoo Yang
- Department of Electrical and Computer Engineering, National University of Singapore
| | - Shunsuke Fukami
- Research Institute of Electrical Communication, Tohoku University
| | - Armin Razavi
- Department of Electrical and Computer Engineering, University of California, Los Angeles
| | - Hao Wu
- Department of Electrical and Computer Engineering, University of California, Los Angeles
| | - Kang Wang
- Department of Electrical and Computer Engineering, University of California, Los Angeles
| | | | | | - Mark D Stiles
- Alternative Computing Group, National Institute of Standards and Technology
| | | | - Axel Hoffmann
- Department of Materials Science and Engineering, University of Illinois Urbana-Champaign
| | | | - Kaushik Roy
- Department of Electrical and Computer Engineering, Purdue University
| | - Jian-Ping Wang
- Electrical and Computer Engineering Department, University of Minnesota
| | | | - Kevin Garello
- IMEC, Leuven, Belgium; CEA-Spintec, Grenoble, France
| | - Wei Zhang
- Physics Department, Oakland University
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18
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Amin VP, Haney PM, Stiles MD. Interfacial spin-orbit torques. JOURNAL OF APPLIED PHYSICS 2020; 128:10.1063/5.0024019. [PMID: 34121763 PMCID: PMC8194107 DOI: 10.1063/5.0024019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 09/30/2020] [Indexed: 06/12/2023]
Abstract
Spin-orbit torques offer a promising mechanism for electrically controlling magnetization dynamics in nanoscale heterostructures. While spin-orbit torques occur predominately at interfaces, the physical mechanisms underlying these torques can originate in both the bulk layers and at interfaces. Classifying spin-orbit torques based on the region that they originate in provides clues as to how to optimize the effect. While most bulk spin-orbit torque contributions are well studied, many of the interfacial contributions allowed by symmetry have yet to be fully explored theoretically and experimentally. To facilitate progress, we review interfacial spin-orbit torques from a semiclassical viewpoint and relate these contributions to recent experimental results. Within the same model, we show the relationship between different interface transport parameters. For charges and spins flowing perpendicular to the interface, interfacial spin-orbit coupling both modifies the mixing conductance of magnetoelectronic circuit theory and gives rise to spin memory loss. For in-plane electric fields, interfacial spin-orbit coupling gives rise to torques described by spin-orbit filtering, spin swapping and precession. In addition, these same interfacial processes generate spin currents that flow into the non-magnetic layer. For in-plane electric fields in trilayer structures, the spin currents generated at the interface between one ferromagnetic layer and the non-magnetic spacer layer can propagate through the non-magnetic layer to produce novel torques on the other ferromagnetic layer.
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Affiliation(s)
- V. P. Amin
- Department of Chemistry & Biochemistry, University of Maryland, College Park, MD 20742, USA
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - P. M. Haney
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - M. D. Stiles
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
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19
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Husain S, Chen X, Gupta R, Behera N, Kumar P, Edvinsson T, García-Sánchez F, Brucas R, Chaudhary S, Sanyal B, Svedlindh P, Kumar A. Large Damping-Like Spin-Orbit Torque in a 2D Conductive 1T-TaS 2 Monolayer. NANO LETTERS 2020; 20:6372-6380. [PMID: 32786947 PMCID: PMC7496736 DOI: 10.1021/acs.nanolett.0c01955] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 08/04/2020] [Indexed: 06/11/2023]
Abstract
A damping-like spin-orbit torque (SOT) is a prerequisite for ultralow-power spin logic devices. Here, we report on the damping-like SOT in just one monolayer of the conducting transition-metal dichalcogenide (TMD) TaS2 interfaced with a NiFe (Py) ferromagnetic layer. The charge-spin conversion efficiency is found to be 0.25 ± 0.03 in TaS2(0.88)/Py(7), and the spin Hall conductivity (14.9×105ℏ2eΩ-1m-1) is found to be superior to values reported for other TMDs. We also observed sizable field-like torque in this heterostructure. The origin of this large damping-like SOT can be found in the interfacial properties of the TaS2/Py heterostructure, and the experimental findings are complemented by the results from density functional theory calculations. It is envisioned that the interplay between interfacial spin-orbit coupling and crystal symmetry yielding large damping-like SOT. The dominance of damping-like torque demonstrated in our study provides a promising path for designing the next-generation conducting TMD-based low-powered quantum memory devices.
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Affiliation(s)
- Sajid Husain
- Department
of Materials Science, Uppsala University, Box 35, SE-751 03 Uppsala, Sweden
| | - Xin Chen
- Department
of Physics and Astronomy, Materials Theory, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
| | - Rahul Gupta
- Department
of Materials Science, Uppsala University, Box 35, SE-751 03 Uppsala, Sweden
| | - Nilamani Behera
- Department
of Materials Science, Uppsala University, Box 35, SE-751 03 Uppsala, Sweden
| | - Prabhat Kumar
- Department
of Thin Films and Nanostructures, Institute
of Physics of the Czech Academy of Sciences, Cukrovarnická 10/112, 162 00 Prague, Czech Republic
| | - Tomas Edvinsson
- Department
of Materials Science, Uppsala University, Box 35, SE-751 03 Uppsala, Sweden
| | - F. García-Sánchez
- Departamento
de Física Aplicada, University of
Salamanca, Pza de la Merced s/n, 37008 Salamanca, Spain
| | - Rimantas Brucas
- Department
of Materials Science, Uppsala University, Box 35, SE-751 03 Uppsala, Sweden
| | - Sujeet Chaudhary
- Thin
Film Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Biplab Sanyal
- Department
of Physics and Astronomy, Materials Theory, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
| | - Peter Svedlindh
- Department
of Materials Science, Uppsala University, Box 35, SE-751 03 Uppsala, Sweden
| | - Ankit Kumar
- Department
of Materials Science, Uppsala University, Box 35, SE-751 03 Uppsala, Sweden
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20
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Liang S, Shi S, Hsu CH, Cai K, Wang Y, He P, Wu Y, Pereira VM, Yang H. Spin-Orbit Torque Magnetization Switching in MoTe 2 /Permalloy Heterostructures. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2002799. [PMID: 32743908 DOI: 10.1002/adma.202002799] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 06/29/2020] [Indexed: 05/27/2023]
Abstract
The ability to switch magnetic elements by spin-orbit-induced torques has recently attracted much attention for a path toward high-performance, nonvolatile memories with low power consumption. Realizing efficient spin-orbit-based switching requires the harnessing of both new materials and novel physics to obtain high charge-to-spin conversion efficiencies, thus making the choice of spin source crucial. Here, the observation of spin-orbit torque switching in bilayers consisting of a semimetallic film of 1T'-MoTe2 adjacent to permalloy is reported. Deterministic switching is achieved without external magnetic fields at room temperature, and the switching occurs with currents one order of magnitude smaller than those typical in devices using the best-performing heavy metals. The thickness-dependence can be understood if the interfacial spin-orbit contribution is considered in addition to the bulk spin Hall effect. Further threefold reduction in the switching current is demonstrated with resort to dumbbell-shaped magnetic elements. These findings foretell exciting prospects of using MoTe2 for low-power semimetal-material-based spin devices.
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Affiliation(s)
- Shiheng Liang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, Singapore
- Faculty of Physics and Electronic Science, Hubei University, Wuhan, 430062, P. R. China
| | - Shuyuan Shi
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, Singapore
| | - Chuang-Han Hsu
- Department of Physics, National University of Singapore, Singapore, 117542, Singapore
- Centre for Advanced 2D Materials, National University of Singapore, Singapore, 117546, Singapore
| | - Kaiming Cai
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, Singapore
| | - Yi Wang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, Singapore
| | - Pan He
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, Singapore
| | - Yang Wu
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, Singapore
| | - Vitor M Pereira
- Department of Physics, National University of Singapore, Singapore, 117542, Singapore
- Centre for Advanced 2D Materials, National University of Singapore, Singapore, 117546, Singapore
| | - Hyunsoo Yang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117576, Singapore
- Centre for Advanced 2D Materials, National University of Singapore, Singapore, 117546, Singapore
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21
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Zhao B, Karpiak B, Khokhriakov D, Johansson A, Hoque AM, Xu X, Jiang Y, Mertig I, Dash SP. Unconventional Charge-Spin Conversion in Weyl-Semimetal WTe 2. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2000818. [PMID: 32776352 DOI: 10.1002/adma.202000818] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 07/08/2020] [Indexed: 05/17/2023]
Abstract
An outstanding feature of topological quantum materials is their novel spin topology in the electronic band structures with an expected large charge-to-spin conversion efficiency. Here, a charge-current-induced spin polarization in the type-II Weyl semimetal candidate WTe2 and efficient spin injection and detection in a graphene channel up to room temperature are reported. Contrary to the conventional spin Hall and Rashba-Edelstein effects, the measurements indicate an unconventional charge-to-spin conversion in WTe2 , which is primarily forbidden by the crystal symmetry of the system. Such a large spin polarization can be possible in WTe2 due to a reduced crystal symmetry combined with its large spin Berry curvature, spin-orbit interaction with a novel spin-texture of the Fermi states. A robust and practical method is demonstrated for electrical creation and detection of such a spin polarization using both charge-to-spin conversion and its inverse phenomenon and utilized it for efficient spin injection and detection in the graphene channel up to room temperature. These findings open opportunities for utilizing topological Weyl materials as nonmagnetic spin sources in all-electrical van der Waals spintronic circuits and for low-power and high-performance nonvolatile spintronic technologies.
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Affiliation(s)
- Bing Zhao
- Beijing Advanced Innovation Center for Materials Genome Engineering, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, 100083, China
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, Göteborg, SE-41296, Sweden
| | - Bogdan Karpiak
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, Göteborg, SE-41296, Sweden
| | - Dmitrii Khokhriakov
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, Göteborg, SE-41296, Sweden
| | - Annika Johansson
- Institute of Physics, Martin Luther University Halle-Wittenberg, Halle, 06099, Germany
- Max Planck Institute of Microstructure Physics, Weinberg 2, Halle, 06120, Germany
| | - Anamul Md Hoque
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, Göteborg, SE-41296, Sweden
| | - Xiaoguang Xu
- Beijing Advanced Innovation Center for Materials Genome Engineering, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Yong Jiang
- Beijing Advanced Innovation Center for Materials Genome Engineering, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Ingrid Mertig
- Institute of Physics, Martin Luther University Halle-Wittenberg, Halle, 06099, Germany
- Max Planck Institute of Microstructure Physics, Weinberg 2, Halle, 06120, Germany
| | - Saroj P Dash
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, Göteborg, SE-41296, Sweden
- Graphene Center, Chalmers University of Technology, Göteborg, SE-41296, Sweden
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22
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Liu Y, Shao Q. Two-Dimensional Materials for Energy-Efficient Spin-Orbit Torque Devices. ACS NANO 2020; 14:9389-9407. [PMID: 32692151 DOI: 10.1021/acsnano.0c04403] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Spin-orbit torques (SOTs), which rely on spin current generation from charge current in a nonmagnetic material, promise an energy-efficient scheme for manipulating magnetization in magnetic devices. A critical topic for spintronic devices using SOTs is to enhance the charge to spin conversion efficiency. Besides, the current-induced spin polarization is usually limited to in-plane, whereas out-of-plane spin polarization could be favored for efficient perpendicular magnetization switching. Recent advances in utilizing two important classes of two-dimensional materials-topological insulators and transition-metal dichalcogenides-as spin sources to generate SOT shed light on addressing these challenges. Topological insulators such as bismuth selenide have shown a giant SOT efficiency, which is larger than those from three-dimensional heavy metals by at least 1 order of magnitude. Transition-metal dichalcogenides such as tungsten telluride have shown a current-induced out-of-plane spin polarization, which is allowed by the reduced symmetry. In this review, we use symmetry arguments to predict and analyze SOTs in two-dimensional material-based heterostructures. We summarize the recent progress of SOT studies based on topological insulators and transition-metal dichalcogenides and show how these results are in line with the symmetry arguments. At last, we identify unsolved issues in the current studies and suggest three potential research directions in this field.
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Affiliation(s)
- Yuting Liu
- Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Qiming Shao
- Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
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23
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Out-of-plane carrier spin in transition-metal dichalcogenides under electric current. Proc Natl Acad Sci U S A 2020; 117:16749-16755. [PMID: 32636257 DOI: 10.1073/pnas.1912472117] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Absence of spatial inversion symmetry allows a nonequilibrium spin polarization to be induced by electric currents, which, in two-dimensional systems, is conventionally analyzed using the Rashba model, leading to in-plane spin polarization. Given that the material realizations of out-of-plane current-induced spin polarization (CISP) are relatively fewer than that of in-plane CISP, but important for perpendicular-magnetization switching and electronic structure evolution, it is highly desirable to search for new prototypical materials and mechanisms to generate the out-of-plane carrier spin and promote the study of CISP. Here, we propose that an out-of-plane CISP can emerge in ferromagnetic transition-metal dichalcogenide monolayers. Taking monolayer [Formula: see text] and [Formula: see text] as examples, we calculate the out-of-plane CISP based on linear-response theory and first-principles methods. We deduce a general low-energy model for easy-plane ferromagnetic transition-metal dichalcogenide monolayers and find that the out-of-plane CISP is due to an in-plane magnetization together with intrinsic spin-orbit coupling inducing an anisotropic out-of-plane spin splitting in the momentum space. The CISP paves the way for magnetization rotation and electric control of the valley quantum number.
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24
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Xu H, Wei J, Zhou H, Feng J, Xu T, Du H, He C, Huang Y, Zhang J, Liu Y, Wu HC, Guo C, Wang X, Guang Y, Wei H, Peng Y, Jiang W, Yu G, Han X. High Spin Hall Conductivity in Large-Area Type-II Dirac Semimetal PtTe 2. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2000513. [PMID: 32176423 DOI: 10.1002/adma.202000513] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 03/02/2020] [Accepted: 03/03/2020] [Indexed: 05/17/2023]
Abstract
Manipulation of magnetization by electric-current-induced spin-orbit torque (SOT) is of great importance for spintronic applications because of its merits in energy-efficient and high-speed operation. An ideal material for SOT applications should possess high charge-spin conversion efficiency and high electrical conductivity. Recently, transition metal dichalcogenides (TMDs) emerge as intriguing platforms for SOT study because of their controllability in spin-orbit coupling, conductivity, and energy band topology. Although TMDs show great potentials in SOT applications, the present study is restricted to the mechanically exfoliated samples with small sizes and relatively low conductivities. Here, a manufacturable recipe is developed to fabricate large-area thin films of PtTe2 , a type-II Dirac semimetal, to study their capability of generating SOT. Large SOT efficiency together with high conductivity results in a giant spin Hall conductivity of PtTe2 thin films, which is the largest value among the presently reported TMDs. It is further demonstrated that the SOT from PtTe2 layer can switch a perpendicularly magnetized CoTb layer efficiently. This work paves the way for employing PtTe2 -like TMDs for wafer-scale spintronic device applications.
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Affiliation(s)
- Hongjun Xu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Jinwu Wei
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Hengan Zhou
- State Key Laboratory of Low-Dimensional Quantum Physics, and Department of Physics, Tsinghua University, Beijing, 100084, China
- Collaborative Innovation Center of Quantum Matter, Beijing, 100084, China
| | - Jiafeng Feng
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Teng Xu
- State Key Laboratory of Low-Dimensional Quantum Physics, and Department of Physics, Tsinghua University, Beijing, 100084, China
- Collaborative Innovation Center of Quantum Matter, Beijing, 100084, China
| | - Haifeng Du
- High Magnetic Field Laboratory, Chinese Academy of Sciences, 350 Shushanhu Road, Hefei, Anhui, 230031, China
| | - Congli He
- Institute of Advanced Materials, Beijing Normal University, Beijing, 100875, China
| | - Yuan Huang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, China
| | - Junwei Zhang
- Key Laboratory of Magnetism and Magnetic Materials of the Ministry of Education, School of Physical Science and Technology and Electron Microscopy Centre of Lanzhou University, Lanzhou University, Lanzhou, 730000, China
| | - Yizhou Liu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Han-Chun Wu
- School of Physics, Beijing Institute of Technology, Beijing, 100081, China
| | - Chenyang Guo
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiao Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yao Guang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Hongxiang Wei
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yong Peng
- Key Laboratory of Magnetism and Magnetic Materials of the Ministry of Education, School of Physical Science and Technology and Electron Microscopy Centre of Lanzhou University, Lanzhou University, Lanzhou, 730000, China
| | - Wanjun Jiang
- State Key Laboratory of Low-Dimensional Quantum Physics, and Department of Physics, Tsinghua University, Beijing, 100084, China
- Collaborative Innovation Center of Quantum Matter, Beijing, 100084, China
| | - Guoqiang Yu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Xiufeng Han
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
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25
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Safeer CK, Ontoso N, Ingla-Aynés J, Herling F, Pham VT, Kurzmann A, Ensslin K, Chuvilin A, Robredo I, Vergniory MG, de Juan F, Hueso LE, Calvo MR, Casanova F. Large Multidirectional Spin-to-Charge Conversion in Low-Symmetry Semimetal MoTe 2 at Room Temperature. NANO LETTERS 2019; 19:8758-8766. [PMID: 31661967 DOI: 10.1021/acs.nanolett.9b03485] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Efficient and versatile spin-to-charge current conversion is crucial for the development of spintronic applications, which strongly rely on the ability to electrically generate and detect spin currents. In this context, the spin Hall effect has been widely studied in heavy metals with strong spin-orbit coupling. While the high crystal symmetry in these materials limits the conversion to the orthogonal configuration, unusual configurations are expected in low-symmetry transition-metal dichalcogenide semimetals, which could add flexibility to the electrical injection and detection of pure spin currents. Here, we report the observation of spin-to-charge conversion in MoTe2 flakes, which are stacked in graphene lateral spin valves. We detect two distinct contributions arising from the conversion of two different spin orientations. In addition to the conventional conversion where the spin polarization is orthogonal to the charge current, we also detect a conversion where the spin polarization and the charge current are parallel. Both contributions, which could arise either from bulk spin Hall effect or surface Edelstein effect, show large efficiencies comparable to the best spin Hall metals and topological insulators. Our finding enables the simultaneous conversion of spin currents with any in-plane spin polarization in one single experimental configuration.
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Affiliation(s)
- C K Safeer
- CIC nanoGUNE , 20018 Donostia-San Sebastian , Basque Country , Spain
| | - Nerea Ontoso
- CIC nanoGUNE , 20018 Donostia-San Sebastian , Basque Country , Spain
| | - Josep Ingla-Aynés
- CIC nanoGUNE , 20018 Donostia-San Sebastian , Basque Country , Spain
| | - Franz Herling
- CIC nanoGUNE , 20018 Donostia-San Sebastian , Basque Country , Spain
| | - Van Tuong Pham
- CIC nanoGUNE , 20018 Donostia-San Sebastian , Basque Country , Spain
| | - Annika Kurzmann
- Solid State Physics Laboratory , ETH Zurich , 8093 Zurich , Switzerland
| | - Klaus Ensslin
- Solid State Physics Laboratory , ETH Zurich , 8093 Zurich , Switzerland
| | - Andrey Chuvilin
- CIC nanoGUNE , 20018 Donostia-San Sebastian , Basque Country , Spain
- IKERBASQUE, Basque Foundation for Science , 48013 Bilbao , Basque Country , Spain
| | - Iñigo Robredo
- Donostia International Physics Center (DIPC) , 20018 Donostia-San Sebastian , Basque Country , Spain
- Department of Condensed Matter Physics , University of the Basque Country (UPV/EHU) , 48080 Bilbao , Basque Country , Spain
| | - Maia G Vergniory
- IKERBASQUE, Basque Foundation for Science , 48013 Bilbao , Basque Country , Spain
- Donostia International Physics Center (DIPC) , 20018 Donostia-San Sebastian , Basque Country , Spain
| | - Fernando de Juan
- IKERBASQUE, Basque Foundation for Science , 48013 Bilbao , Basque Country , Spain
- Donostia International Physics Center (DIPC) , 20018 Donostia-San Sebastian , Basque Country , Spain
| | - Luis E Hueso
- CIC nanoGUNE , 20018 Donostia-San Sebastian , Basque Country , Spain
- IKERBASQUE, Basque Foundation for Science , 48013 Bilbao , Basque Country , Spain
| | - M Reyes Calvo
- CIC nanoGUNE , 20018 Donostia-San Sebastian , Basque Country , Spain
- IKERBASQUE, Basque Foundation for Science , 48013 Bilbao , Basque Country , Spain
- Departamento de Física Aplicada , Universidad de Alicante , 03690 Alicante , Spain
| | - Fèlix Casanova
- CIC nanoGUNE , 20018 Donostia-San Sebastian , Basque Country , Spain
- IKERBASQUE, Basque Foundation for Science , 48013 Bilbao , Basque Country , Spain
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Shi S, Liang S, Zhu Z, Cai K, Pollard SD, Wang Y, Wang J, Wang Q, He P, Yu J, Eda G, Liang G, Yang H. All-electric magnetization switching and Dzyaloshinskii-Moriya interaction in WTe 2/ferromagnet heterostructures. NATURE NANOTECHNOLOGY 2019; 14:945-949. [PMID: 31427750 DOI: 10.1038/s41565-019-0525-8] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 07/16/2019] [Indexed: 05/17/2023]
Abstract
All-electric magnetization manipulation at low power is a prerequisite for a wide adoption of spintronic devices. Materials such as heavy metals1-3 or topological insulators4,5 provide good charge-to-spin conversion efficiencies. They enable magnetization switching in heterostructures with either metallic ferromagnets or with magnetic insulators. Recent work suggests a pronounced Edelstein effect in Weyl semimetals due to their non-trivial band structure6,7; the Edelstein effect can be one order of magnitude stronger than it is in topological insulators or Rashba systems. Furthermore, the strong intrinsic spin Hall effect from the bulk states in Weyl semimetals can contribute to the spin current generation8. The Td phase of the Weyl semimetal WTe2 (WTe2 hereafter) possesses strong spin-orbit coupling6,9 and non-trivial band structures10 with a large spin polarization protected by time-reversal symmetry in both the surface and bulk states9-11. Atomically flat surfaces, which can be produced with high quality12, facilitate spintronic device applications. Here, we use WTe2 as a spin current source in WTe2/Ni81Fe19 (Py) heterostructures. We report field-free current-induced magnetization switching at room temperature. A charge current density of ~2.96 × 105 A cm-2 suffices to switch the magnetization of the Py layer. With the charge current along the b axis of the WTe2 layer, the thickness-dependent charge-to-spin conversion efficiency reaches 0.51 at 6-7 GHz. At the WTe2/Py interface, a Dzyaloshinskii-Moriya interaction (DMI) with a DMI constant of -1.78 ± 0.06 mJ m-2 induces chiral domain wall tilting. Our study demonstrates the capability of WTe2 to efficiently manipulate magnetization and sheds light on the role of the interface in Weyl semimetal/magnet heterostructures.
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Affiliation(s)
- Shuyuan Shi
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
- Centre for Advanced 2D Materials, National University of Singapore, Singapore, Singapore
| | - Shiheng Liang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Zhifeng Zhu
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Kaiming Cai
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Shawn D Pollard
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Yi Wang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Junyong Wang
- Centre for Advanced 2D Materials, National University of Singapore, Singapore, Singapore
- Department of Physics, National University of Singapore, Singapore, Singapore
| | - Qisheng Wang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Pan He
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Jiawei Yu
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Goki Eda
- Centre for Advanced 2D Materials, National University of Singapore, Singapore, Singapore
- Department of Physics, National University of Singapore, Singapore, Singapore
- Department of Chemistry, National University of Singapore, Singapore, Singapore
| | - Gengchiau Liang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
| | - Hyunsoo Yang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore.
- Centre for Advanced 2D Materials, National University of Singapore, Singapore, Singapore.
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Stiehl GM, MacNeill D, Sivadas N, El Baggari I, Guimarães MHD, Reynolds ND, Kourkoutis LF, Fennie CJ, Buhrman RA, Ralph DC. Current-Induced Torques with Dresselhaus Symmetry Due to Resistance Anisotropy in 2D Materials. ACS NANO 2019; 13:2599-2605. [PMID: 30615411 DOI: 10.1021/acsnano.8b09663] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We report measurements of current-induced torques in heterostructures of Permalloy (Py) with TaTe2, a transition-metal dichalcogenide (TMD) material possessing low crystal symmetry, and observe a torque component with Dresselhaus symmetry. We suggest that the dominant mechanism for this Dresselhaus component is not a spin-orbit torque but rather the Oersted field arising from a component of current that flows perpendicular to the applied voltage due to resistance anisotropy within the TaTe2. This type of transverse current is not present in wires made from a single uniform layer of a material with resistance anisotropy but will result whenever a material with resistance anisotropy is integrated into a heterostructure with materials having different resistivities, thereby producing a spatially nonuniform pattern of current flow. This effect will therefore influence measurements in a wide variety of heterostructures incorporating 2D TMD materials and other materials with low crystal symmetries.
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Affiliation(s)
- Gregory M Stiehl
- Department of Physics , Cornell University , Ithaca , New York 14853 , United States
| | - David MacNeill
- Department of Physics , Cornell University , Ithaca , New York 14853 , United States
| | - Nikhil Sivadas
- School of Applied and Engineering Physics , Cornell University , Ithaca , New York 14853 , United States
| | - Ismail El Baggari
- School of Applied and Engineering Physics , Cornell University , Ithaca , New York 14853 , United States
| | - Marcos H D Guimarães
- Department of Physics , Cornell University , Ithaca , New York 14853 , United States
- Kavli Institute at Cornell , Cornell University , Ithaca , New York 14853 , United States
| | - Neal D Reynolds
- Department of Physics , Cornell University , Ithaca , New York 14853 , United States
| | - Lena F Kourkoutis
- School of Applied and Engineering Physics , Cornell University , Ithaca , New York 14853 , United States
- Kavli Institute at Cornell , Cornell University , Ithaca , New York 14853 , United States
| | - Craig J Fennie
- Department of Physics , Cornell University , Ithaca , New York 14853 , United States
| | - Robert A Buhrman
- School of Applied and Engineering Physics , Cornell University , Ithaca , New York 14853 , United States
| | - Daniel C Ralph
- Department of Physics , Cornell University , Ithaca , New York 14853 , United States
- Kavli Institute at Cornell , Cornell University , Ithaca , New York 14853 , United States
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28
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Guimarães MHD, Koopmans B. Spin Accumulation and Dynamics in Inversion-Symmetric van der Waals Crystals. PHYSICAL REVIEW LETTERS 2018; 120:266801. [PMID: 30004759 DOI: 10.1103/physrevlett.120.266801] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 04/25/2018] [Indexed: 06/08/2023]
Abstract
Inversion-symmetric materials are forbidden to show an overall spin texture in their band structure in the presence of time-reversal symmetry. However, in van der Waals materials which lack inversion symmetry within a single layer, it has been proposed that a layer-dependent spin texture can arise leading to a coupled spin-layer degree of freedom. Here we use time-resolved Kerr rotation in inversion-symmetric WSe_{2} and MoSe_{2} bulk crystals to study this spin-layer polarization and unveil its dynamics. Our measurements show that the spin-layer relaxation time in WSe_{2} is limited by phonon scattering at high temperatures and that the interlayer hopping can be tuned by a small in-plane magnetic field at low temperatures, enhancing the relaxation rates. We find a significantly lower lifetime for MoSe_{2} which agrees with theoretical expectations of a spin-layer polarization stabilized by the larger spin-orbit coupling in WSe_{2}.
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Affiliation(s)
- M H D Guimarães
- Department of Applied Physics, Eindhoven University of Technology, Eindhoven, Netherlands
| | - B Koopmans
- Department of Applied Physics, Eindhoven University of Technology, Eindhoven, Netherlands
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