1
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Ngaloy R, Zhao B, Ershadrad S, Gupta R, Davoudiniya M, Bainsla L, Sjöström L, Hoque MA, Kalaboukhov A, Svedlindh P, Sanyal B, Dash SP. Strong In-Plane Magnetization and Spin Polarization in (Co 0.15Fe 0.85) 5GeTe 2/Graphene van der Waals Heterostructure Spin-Valve at Room Temperature. ACS NANO 2024. [PMID: 38330915 PMCID: PMC10883121 DOI: 10.1021/acsnano.3c07462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2024]
Abstract
Van der Waals (vdW) magnets are promising, because of their tunable magnetic properties with doping or alloy composition, where the strength of magnetic interactions, their symmetry, and magnetic anisotropy can be tuned according to the desired application. However, so far, most of the vdW magnet-based spintronic devices have been limited to cryogenic temperatures with magnetic anisotropies favoring out-of-plane or canted orientation of the magnetization. Here, we report beyond room-temperature lateral spin-valve devices with strong in-plane magnetization and spin polarization of the vdW ferromagnet (Co0.15Fe0.85)5GeTe2 (CFGT) in heterostructures with graphene. Density functional theory (DFT) calculations show that the magnitude of the anisotropy depends on the Co concentration and is caused by the substitution of Co in the outermost Fe layer. Magnetization measurements reveal the above room-temperature ferromagnetism in CFGT and clear remanence at room temperature. Heterostructures consisting of CFGT nanolayers and graphene were used to experimentally realize basic building blocks for spin valve devices, such as efficient spin injection and detection. Further analysis of spin transport and Hanle spin precession measurements reveals a strong in-plane magnetization with negative spin polarization at the interface with graphene, which is supported by the calculated spin-polarized density of states of CFGT. The in-plane magnetization of CFGT at room temperature proves its usefulness in graphene lateral spin-valve devices, thus revealing its potential application in spintronic technologies.
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Affiliation(s)
- Roselle Ngaloy
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296 Göteborg, Sweden
| | - Bing Zhao
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296 Göteborg, Sweden
| | - Soheil Ershadrad
- Department of Physics and Astronomy, Uppsala University, Box-516, 75120 Uppsala, Sweden
| | - Rahul Gupta
- Department of Physics and Astronomy, Uppsala University, Box-516, 75120 Uppsala, Sweden
- Department of Materials Science and Engineering, Uppsala University, Box 35, SE-751 03 Uppsala, Sweden
| | - Masoumeh Davoudiniya
- Department of Physics and Astronomy, Uppsala University, Box-516, 75120 Uppsala, Sweden
| | - Lakhan Bainsla
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296 Göteborg, Sweden
- Department of Physics, Indian Institute of Technology Ropar, Roopnagar 140001, Punjab, India
| | - Lars Sjöström
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296 Göteborg, Sweden
| | - Md Anamul Hoque
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296 Göteborg, Sweden
| | - Alexei Kalaboukhov
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296 Göteborg, Sweden
| | - Peter Svedlindh
- Department of Materials Science and Engineering, Uppsala University, Box 35, SE-751 03 Uppsala, Sweden
| | - Biplab Sanyal
- Department of Physics and Astronomy, Uppsala University, Box-516, 75120 Uppsala, Sweden
| | - Saroj Prasad Dash
- 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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2
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Xu J, Ping Y. Ab Initio Predictions of Spin Relaxation, Dephasing, and Diffusion in Solids. J Chem Theory Comput 2024; 20:492-512. [PMID: 38157422 DOI: 10.1021/acs.jctc.3c00598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
Spin relaxation, dephasing, and diffusion are at the heart of spin-based information technology. Accurate theoretical approaches to simulate spin lifetimes (τs), determining how fast the spin polarization and phase information will be lost, are important to the understanding of the underlying mechanism of these spin processes, and invaluable in searching for promising candidates of spintronic materials. Recently, we develop a first-principles real-time density-matrix (FPDM) approach to simulate spin dynamics for general solid-state systems. Through the complete first-principles descriptions of light-matter interaction and scattering processes including electron-phonon, electron-impurity, and electron-electron scatterings with self-consistent spin-orbit coupling, as well as ab initio Landé g-factor, our method can predict τs at various conditions as a function of carrier density and temperature, under electric and magnetic fields. By employing this method, we successfully reproduce experimental results of disparate materials and identify the key factors affecting spin relaxation, dephasing, and diffusion in different materials. Specifically, we predict that germanene has long τs (∼100 ns at 50 K), a giant spin lifetime anisotropy, and spin-valley locking effect under electric fields, making it advantageous for spin-valleytronic applications. Based on our theoretical derivations and ab initio simulations, we propose a new useful electronic quantity, named spin-flip angle θ↑↓, for the understanding of spin relaxation through intervalley spin-flip scattering processes. Our method can be further applied to other emerging materials and extended to simulate exciton spin dynamics and steady-state photocurrents due to photogalvanic effect.
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Affiliation(s)
- Junqing Xu
- Department of Physics, Hefei University of Technology, Hefei 230031, Anhui China
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, United States
| | - Yuan Ping
- Department of Materials Science and Engineering, University of Wisconsin─Madison, Madison, Wisconsin 53706, United States
- Department of Physics, University of California, Santa Cruz, California 95064, United States
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3
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Li Y, Zhou K, Ci H, Sun J. Recent Advances in Transfer-Free Synthesis of High-Quality Graphene. CHEMSUSCHEM 2023; 16:e202300865. [PMID: 37491687 DOI: 10.1002/cssc.202300865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Revised: 07/25/2023] [Accepted: 07/25/2023] [Indexed: 07/27/2023]
Abstract
High-quality graphene obtained by chemical vapor deposition (CVD) technique holds significant importance in constructing innovative electronic and optoelectronic devices. Direct growth of graphene over target substrates readily eliminates cumbersome transfer processes, offering compatibility with practical application scenarios. Recent years have witnessed growing strategic endeavors in the preparation of transfer-free graphene with favorable quality. Nevertheless, timely review articles on this topic are still scarce. In this contribution, a systematic summary of recent advances in transfer-free synthesis of high-quality graphene on insulating substrates, with a focus on discussing synthetic strategies designed by elevating reaction temperature, confining gas flow, introducing growth promotor and regulating substrate surface is presented.
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Affiliation(s)
- Yinghan Li
- College of Energy, Soochow Institute for Energy and Materials Innovations, SUDA-BGI Collaborative Innovation Center, Key Laboratory of Advanced Carbon Materials and Wearable Energy Technologies of Jiangsu Province, Soochow University, Suzhou, 215006, P. R. China
- Beijing Graphene Institute, Beijing, 100095, P. R. China
| | - Kaixuan Zhou
- College of Energy, Soochow Institute for Energy and Materials Innovations, SUDA-BGI Collaborative Innovation Center, Key Laboratory of Advanced Carbon Materials and Wearable Energy Technologies of Jiangsu Province, Soochow University, Suzhou, 215006, P. R. China
- Beijing Graphene Institute, Beijing, 100095, P. R. China
| | - Haina Ci
- College of Electromechanical Engineering, Qingdao University of Science and Technology, Qingdao, 266061, P. R. China
| | - Jingyu Sun
- College of Energy, Soochow Institute for Energy and Materials Innovations, SUDA-BGI Collaborative Innovation Center, Key Laboratory of Advanced Carbon Materials and Wearable Energy Technologies of Jiangsu Province, Soochow University, Suzhou, 215006, P. R. China
- Beijing Graphene Institute, Beijing, 100095, P. R. China
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4
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Fan Z, Liu Y, Wei X, Zhu W, Huang H, Shao Q, Liao F, Shao M, Li W, Mu G, Liu Y, Kang Z. Emergent Intrinsic Ferromagnetism in Two-Dimensional Trigonal Rhodium Oxide. NANO LETTERS 2023; 23:9515-9521. [PMID: 37830516 DOI: 10.1021/acs.nanolett.3c03087] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/14/2023]
Abstract
Two-dimensional (2D) van der Waals single crystals with long-range magnetic order are the precondition and urgent task for developing a 2D spintronics device. In contrast to graphene and transition metal dichalcogenides, the study of 2D single-crystal metal oxides with intrinsic ferromagnetic properties remains a huge challenge. Here, we report a large-size trigonal single-crystal rhodium oxide (SC-Tri-RhO2), with crystal parameters of a = b = 3.074 Å, c = 6.116 Å, and a space group of P3̅m1 (164), exhibiting strong ferromagnetism (FM) at a rather high temperature. Furthermore, theoretical calculations suggest that the ferromagnetism in SC-Tri-RhO2 originates from spin splitting near the Fermi level, and the total magnetic moment is contributed mainly by the Rh atom.
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Affiliation(s)
- Zhenglong Fan
- Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123, Jiangsu, China
| | - Yixin Liu
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China
| | - Xinyuan Wei
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
| | - Wenxiang Zhu
- Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123, Jiangsu, China
| | - Hui Huang
- Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123, Jiangsu, China
| | - Qi Shao
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, Jiangsu, China
| | - Fan Liao
- Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123, Jiangsu, China
| | - Mingwang Shao
- Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123, Jiangsu, China
| | - Wei Li
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
| | - Gang Mu
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China
| | - Yang Liu
- Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123, Jiangsu, China
| | - Zhenhui Kang
- Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123, Jiangsu, China
- Macao Institute of Materials Science and Engineering (MIMSE), MUST-SUDA Joint Research Center for Advanced Functional Materials, Macau University of Science and Technology, Taipa 999078, Macao, China
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5
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Ghising P, Biswas C, Lee YH. Graphene Spin Valves for Spin Logic Devices. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2209137. [PMID: 36618004 DOI: 10.1002/adma.202209137] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 11/23/2022] [Indexed: 06/09/2023]
Abstract
An alternative to charge-based electronics identifies the spin degree of freedom for information communication and processing. The long spin-diffusion length in graphene at room temperature demonstrates its ability for highly scalable spintronics. The development of the graphene spin valve (SV) has inspired spin devices in graphene including spin field-effect transistors and spin majority logic gates. A comprehensive picture of spin transport in graphene SVs is required for further development of spin logic. This review examines the advances in graphene SVs and their role in the development of spin logic devices. Different transport and scattering mechanisms in charge and spin are discussed. Furthermore, the on/off switching energy between graphene SVs and charge-based FETs is compared to highlight their prospects for low-power devices. The challenges and perspectives that need to be addressed for the future development of spin logic devices are then outlined.
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Affiliation(s)
- Pramod Ghising
- Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Chandan Biswas
- Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
| | - Young Hee Lee
- Center for Integrated Nanostructure Physics, Institute for Basic Science (IBS), Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
- Department of Energy Science, Department of Physics, Sungkyunkwan University, Suwon, 16419, Republic of Korea
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6
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Márkus BG, Gmitra M, Dóra B, Csősz G, Fehér T, Szirmai P, Náfrádi B, Zólyomi V, Forró L, Fabian J, Simon F. Ultralong 100 ns spin relaxation time in graphite at room temperature. Nat Commun 2023; 14:2831. [PMID: 37198155 DOI: 10.1038/s41467-023-38288-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 04/24/2023] [Indexed: 05/19/2023] Open
Abstract
Graphite has been intensively studied, yet its electron spins dynamics remains an unresolved problem even 70 years after the first experiments. The central quantities, the longitudinal (T1) and transverse (T2) relaxation times were postulated to be equal, mirroring standard metals, but T1 has never been measured for graphite. Here, based on a detailed band structure calculation including spin-orbit coupling, we predict an unexpected behavior of the relaxation times. We find, based on saturation ESR measurements, that T1 is markedly different from T2. Spins injected with perpendicular polarization with respect to the graphene plane have an extraordinarily long lifetime of 100 ns at room temperature. This is ten times more than in the best graphene samples. The spin diffusion length across graphite planes is thus expected to be ultralong, on the scale of ~ 70 μm, suggesting that thin films of graphite - or multilayer AB graphene stacks - can be excellent platforms for spintronics applications compatible with 2D van der Waals technologies. Finally, we provide a qualitative account of the observed spin relaxation based on the anisotropic spin admixture of the Bloch states in graphite obtained from density functional theory calculations.
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Affiliation(s)
- B G Márkus
- Stavropoulos Center for Complex Quantum Matter, Department of Physics and Astronomy, University of Notre Dame, Notre Dame, IN, 46556, USA
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Budapest, H-1525, Hungary
- Department of Physics, Institute of Physics, Budapest University of Technology and Economics, Műegyetem rkp. 3., H-1111, Budapest, Hungary
| | - M Gmitra
- Institute of Physics, Pavol Jozef Šafárik University in Košice, Park Angelinum 9, 040 01, Košice, Slovakia
- Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, 04001, Košice, Slovakia
| | - B Dóra
- Department of Theoretical Physics, Institute of Physics and MTA-BME Lendület Topology and Correlation Research Group Budapest University of Technology and Economics, Műegyetem rkp. 3., H-1111, Budapest, Hungary
| | - G Csősz
- Department of Physics, Institute of Physics, Budapest University of Technology and Economics, Műegyetem rkp. 3., H-1111, Budapest, Hungary
| | - T Fehér
- Department of Physics, Institute of Physics, Budapest University of Technology and Economics, Műegyetem rkp. 3., H-1111, Budapest, Hungary
| | - P Szirmai
- Laboratory of Physics of Complex Matter, École Polytechnique Fédérale de Lausanne, Lausanne, CH-1015, Switzerland
| | - B Náfrádi
- Laboratory of Physics of Complex Matter, École Polytechnique Fédérale de Lausanne, Lausanne, CH-1015, Switzerland
| | - V Zólyomi
- STFC Hartree Centre, Daresbury Laboratory, Daresbury, Warrington WA4 4AD, UK
| | - L Forró
- Stavropoulos Center for Complex Quantum Matter, Department of Physics and Astronomy, University of Notre Dame, Notre Dame, IN, 46556, USA
- Laboratory of Physics of Complex Matter, École Polytechnique Fédérale de Lausanne, Lausanne, CH-1015, Switzerland
| | - J Fabian
- Department of Physics, University of Regensburg, 93040, Regensburg, Germany.
| | - F Simon
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Budapest, H-1525, Hungary.
- Department of Physics, Institute of Physics and ELKH-BME Condensed Matter Research Group Budapest University of Technology and Economics, Műegyetem rkp. 3., H-1111, Budapest, Hungary.
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7
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Belotcerkovtceva D, Maciel RP, Berggren E, Maddu R, Sarkar T, Kvashnin YO, Thonig D, Lindblad A, Eriksson O, Kamalakar MV. Insights and Implications of Intricate Surface Charge Transfer and sp 3-Defects in Graphene/Metal Oxide Interfaces. ACS APPLIED MATERIALS & INTERFACES 2022; 14:36209-36216. [PMID: 35867345 PMCID: PMC9376919 DOI: 10.1021/acsami.2c06626] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 06/29/2022] [Indexed: 06/15/2023]
Abstract
Adherence of metal oxides to graphene is of fundamental significance to graphene nanoelectronic and spintronic interfaces. Titanium oxide and aluminum oxide are two widely used tunnel barriers in such devices, which offer optimum interface resistance and distinct interface conditions that govern transport parameters and device performance. Here, we reveal a fundamental difference in how these metal oxides interface with graphene through electrical transport measurements and Raman and photoelectron spectroscopies, combined with ab initio electronic structure calculations of such interfaces. While both oxide layers cause surface charge transfer induced p-type doping in graphene, in sharp contrast to TiOx, the AlOx/graphene interface shows the presence of appreciable sp3 defects. Electronic structure calculations disclose that significant p-type doping occurs due to a combination of sp3 bonds formed between C and O atoms at the interface and possible slightly off-stoichiometric defects of the aluminum oxide layer. Furthermore, the sp3 hybridization at the AlOx/graphene interface leads to distinct magnetic moments of unsaturated bonds, which not only explicates the widely observed low spin-lifetimes in AlOx barrier graphene spintronic devices but also suggests possibilities for new hybrid resistive switching and spin valves.
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Affiliation(s)
- Daria Belotcerkovtceva
- Department
of Physics and Astronomy, Uppsala University, P.O. Box 516, SE-751 20 Uppsala, Sweden
| | - Renan P. Maciel
- Department
of Physics and Astronomy, Uppsala University, P.O. Box 516, SE-751 20 Uppsala, Sweden
| | - Elin Berggren
- Department
of Physics and Astronomy, Uppsala University, P.O. Box 516, SE-751 20 Uppsala, Sweden
| | - Ramu Maddu
- Department
of Materials Science and Engineering, Uppsala
University, P.O. Box 35, SE-751 03 Uppsala, Sweden
| | - Tapati Sarkar
- Department
of Materials Science and Engineering, Uppsala
University, P.O. Box 35, SE-751 03 Uppsala, Sweden
| | - Yaroslav O. Kvashnin
- Department
of Physics and Astronomy, Uppsala University, P.O. Box 516, SE-751 20 Uppsala, Sweden
| | - Danny Thonig
- Department
of Physics and Astronomy, Uppsala University, P.O. Box 516, SE-751 20 Uppsala, Sweden
- School
of Science and Technology, Örebro
University, Fakultetsgatan
1, SE-70182 Örebro, Sweden
| | - Andreas Lindblad
- Department
of Physics and Astronomy, Uppsala University, P.O. Box 516, SE-751 20 Uppsala, Sweden
| | - Olle Eriksson
- Department
of Physics and Astronomy, Uppsala University, P.O. Box 516, SE-751 20 Uppsala, Sweden
- School
of Science and Technology, Örebro
University, Fakultetsgatan
1, SE-70182 Örebro, Sweden
| | - M. Venkata Kamalakar
- Department
of Physics and Astronomy, Uppsala University, P.O. Box 516, SE-751 20 Uppsala, Sweden
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8
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Phung TT, Nguyen MT, Pham LT, Ngo LT, Nguyen TT. Edge magnetization and thermally induced spin current in nanostructured graphene. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:315801. [PMID: 35623336 DOI: 10.1088/1361-648x/ac742a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Accepted: 05/26/2022] [Indexed: 06/15/2023]
Abstract
In this work, the magnetic states and thermally induced spin currents in graphene nanoflake sizes with different sizes and shapes have been investigated using Hubbard model combined with non-equilibrium Green's function method. In addition to the antiferromagnetic (AFM) state governed by the sizes, shapes, armchair bond densities, and Coulomb energy, our calculations have also pointed out the emergence of ferromagnetic (FM) and complex magnetic states when the gate voltage is invoked in the graphene nanoflakes. More prominently, by exploiting the geometric symmetry of the nanoflakes without external fields, a pure spin current and zero charge current are generated in spin caloritronic device when the graphene nanoflakes are both in the AFM and FM states. The formation of pure spin currents driven by temperature difference depends on the graphene nanoflakes' size, shape, temperature and gate voltage as well. The study also shows the outstanding advantages of diamond-shaped graphene nanoflakes in both magnetic properties and spin currents. This result paves the way for the possibility of practical applications of graphene materials in spintronics and spin caloritronics.
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Affiliation(s)
- Thu Thi Phung
- Graduate University of Science and Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Ha Noi, Vietnam
- University of Science and Technology of Hanoi, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Ha Noi, Vietnam
| | - Mai Thi Nguyen
- Institute of Material Sciences, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Ha Noi, Vietnam
| | - Lien Thi Pham
- Institute of Material Sciences, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Ha Noi, Vietnam
| | - Lan Thi Ngo
- Institute of Science and Technology, TNU-University of Science, Tan Thinh Ward, Thai Nguyen, Vietnam
| | - Tung Thanh Nguyen
- Institute of Material Sciences, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Ha Noi, Vietnam
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9
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Pal A, Zhang S, Chavan T, Agashiwala K, Yeh CH, Cao W, Banerjee K. Quantum-Engineered Devices Based on 2D Materials for Next-Generation Information Processing and Storage. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022:e2109894. [PMID: 35468661 DOI: 10.1002/adma.202109894] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 04/11/2022] [Indexed: 06/14/2023]
Abstract
As an approximation to the quantum state of solids, the band theory, developed nearly seven decades ago, fostered the advance of modern integrated solid-state electronics, one of the most successful technologies in the history of human civilization. Nonetheless, their rapidly growing energy consumption and accompanied environmental issues call for more energy-efficient electronics and optoelectronics, which necessitate the exploration of more advanced quantum mechanical effects, such as band-to-band tunneling, spin-orbit coupling, spin-valley locking, and quantum entanglement. The emerging 2D layered materials, featured by their exotic electrical, magnetic, optical, and structural properties, provide a revolutionary low-dimensional and manufacture-friendly platform (and many more opportunities) to implement these quantum-engineered devices, compared to the traditional electronic materials system. Here, the progress in quantum-engineered devices is reviewed and the opportunities/challenges of exploiting 2D materials are analyzed to highlight their unique quantum properties that enable novel energy-efficient devices, and useful insights to quantum device engineers and 2D-material scientists are provided.
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Affiliation(s)
- Arnab Pal
- ECE Department, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Shuo Zhang
- ECE Department, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA
- College of ISEE, Zhejiang University, Hangzhou, 310027, China
| | - Tanmay Chavan
- ECE Department, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Kunjesh Agashiwala
- ECE Department, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Chao-Hui Yeh
- ECE Department, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Wei Cao
- ECE Department, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Kaustav Banerjee
- ECE Department, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA
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10
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He K, Barut B, Yin S, Randle MD, Dixit R, Arabchigavkani N, Nathawat J, Mahmood A, Echtenkamp W, Binek C, Dowben PA, Bird JP. Graphene on Chromia: A System for Beyond-Room-Temperature Spintronics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2105023. [PMID: 34986269 DOI: 10.1002/adma.202105023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 12/23/2021] [Indexed: 06/14/2023]
Abstract
Evidence of robust spin-dependent transport in monolayer graphene, deposited on the (0001) surface of the antiferromagnetic (AFM)/magneto-electric oxide chromia (Cr2 O3 ), is provided. Measurements performed in the non-local spin-Hall geometry reveal a robust signal that is present at zero external magnetic field and which is significantly larger than any possible ohmic contribution. The spin-related signal persists well beyond the Néel temperature (≈307 K) that defines the transition between the AFM and paramagnetic states, remaining visible at the highest studied temperature of close to 450 K. This robust character is consistent with prior theoretical studies of the graphene/Cr2 O3 system, predicting that the lifting of sub-lattice symmetry in the graphene shall induce an effective spin-orbit term of ≈40 meV. Overall, the results indicate that graphene-on-chromia heterostructures are a highly promising framework for the implementation of spintronic devices, capable of operation well beyond room temperature.
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Affiliation(s)
- Keke He
- Department of Electrical Engineering, University at Buffalo, The State University of New York, Buffalo, New York, 14260, USA
| | - Bilal Barut
- Department of Electrical Engineering, University at Buffalo, The State University of New York, Buffalo, New York, 14260, USA
| | - Shenchu Yin
- Department of Electrical Engineering, University at Buffalo, The State University of New York, Buffalo, New York, 14260, USA
| | - Michael D Randle
- Department of Electrical Engineering, University at Buffalo, The State University of New York, Buffalo, New York, 14260, USA
| | - Ripudaman Dixit
- Department of Electrical Engineering, University at Buffalo, The State University of New York, Buffalo, New York, 14260, USA
| | - Nargess Arabchigavkani
- Department of Electrical Engineering, University at Buffalo, The State University of New York, Buffalo, New York, 14260, USA
| | - Jubin Nathawat
- Department of Electrical Engineering, University at Buffalo, The State University of New York, Buffalo, New York, 14260, USA
| | - Ather Mahmood
- Department of Physics and Astronomy, Theodore Jorgensen Hall, University of Nebraska Lincoln, Lincoln, Nebraska, 68588-0299, USA
| | - Will Echtenkamp
- Department of Physics and Astronomy, Theodore Jorgensen Hall, University of Nebraska Lincoln, Lincoln, Nebraska, 68588-0299, USA
| | - Christian Binek
- Department of Physics and Astronomy, Theodore Jorgensen Hall, University of Nebraska Lincoln, Lincoln, Nebraska, 68588-0299, USA
| | - Peter A Dowben
- Department of Physics and Astronomy, Theodore Jorgensen Hall, University of Nebraska Lincoln, Lincoln, Nebraska, 68588-0299, USA
| | - Jonathan P Bird
- Department of Electrical Engineering, University at Buffalo, The State University of New York, Buffalo, New York, 14260, USA
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11
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de Araujo CIL, Teixeira HA, Toro OO, Liao C, Benetti LC, Borme J, Schafer D, Brandt I, Ferreira R, Alpuim P, Freitas PP, Pasa AA. Room temperature two terminal tunnel magnetoresistance in a lateral graphene transistor. NANOSCALE 2021; 13:20028-20033. [PMID: 34842882 DOI: 10.1039/d1nr05495c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We investigate the behavior of both pure spin and spin-polarized currents measured with four-probe non-local and two probe local configurations up to room temperature and under an external gate voltage in a lateral graphene transistor, produced using a standard large-scale microfabrication process. The high spin diffusion length of pristine graphene in the channel, measured both directly and by the Hanle effect, and the tuning of the relationship between the electrode resistance areas present in the device architecture allowed us to observe local tunnel magnetoresistance at room temperature, a new finding for this type of device. The results also indicate that while pure spin currents are less sensitive to temperature variations, spin-polarized current switching by an external voltage is more efficient, due to a combination of the Rashba effect and a change in carrier mobility by a Fermi level shift.
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Affiliation(s)
- C I L de Araujo
- Departamento de Fìsica, Laboratório de Spintrônica e Nanomagnetismo, Universidade Federal de Viçosa, Viçosa, 36570-900, Minas Gerais, Brazil.
| | - H A Teixeira
- Departamento de Fìsica, Laboratório de Spintrônica e Nanomagnetismo, Universidade Federal de Viçosa, Viçosa, 36570-900, Minas Gerais, Brazil.
| | - O O Toro
- Departamento de Fìsica, Laboratório de Spintrônica e Nanomagnetismo, Universidade Federal de Viçosa, Viçosa, 36570-900, Minas Gerais, Brazil.
| | - C Liao
- INL-International Iberian Nanotechnology Laboratory, 4715-330, Braga, Portugal
| | - L C Benetti
- INL-International Iberian Nanotechnology Laboratory, 4715-330, Braga, Portugal
- Laboratório de Filmes Finos e Superfícies (LFFS), Universidade Federal de Santa Catarina, Florianópolis 88040-900, Brazil
| | - J Borme
- INL-International Iberian Nanotechnology Laboratory, 4715-330, Braga, Portugal
| | - D Schafer
- Laboratório de Filmes Finos e Superfícies (LFFS), Universidade Federal de Santa Catarina, Florianópolis 88040-900, Brazil
| | - I Brandt
- Laboratório de Filmes Finos e Superfícies (LFFS), Universidade Federal de Santa Catarina, Florianópolis 88040-900, Brazil
| | - R Ferreira
- INL-International Iberian Nanotechnology Laboratory, 4715-330, Braga, Portugal
| | - P Alpuim
- INL-International Iberian Nanotechnology Laboratory, 4715-330, Braga, Portugal
| | - Paulo P Freitas
- INL-International Iberian Nanotechnology Laboratory, 4715-330, Braga, Portugal
| | - A A Pasa
- Laboratório de Filmes Finos e Superfícies (LFFS), Universidade Federal de Santa Catarina, Florianópolis 88040-900, Brazil
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12
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Xu J, Takenaka H, Habib A, Sundararaman R, Ping Y. Giant Spin Lifetime Anisotropy and Spin-Valley Locking in Silicene and Germanene from First-Principles Density-Matrix Dynamics. NANO LETTERS 2021; 21:9594-9600. [PMID: 34767368 DOI: 10.1021/acs.nanolett.1c03345] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Through first-principles real-time density-matrix (FPDM) dynamics simulations, we investigated spin relaxation due to electron-phonon and electron-impurity scatterings with spin-orbit coupling (SOC) in two-dimensional Dirac materials silicene and germanene at finite temperatures. We discussed the applicability of conventional descriptions of spin relaxation mechanisms by Elliott-Yafet (EY) and D'yakonov-Perel' (DP) compared to the FPDM method, which is determined by a complex interplay of intrinsic SOC, external fields, and scattering strength. For example, the electric field dependence of the spin lifetime by FPDM is close to the DP mechanism for silicene at room temperature but similar to the EY mechanism for germanene. Because of its stronger SOC strength and buckled structure in contrast to graphene, germanene has a giant spin lifetime anisotropy and spin-valley locking effect under nonzero Ez and low temperatures. More importantly, germanene has a long spin lifetime (∼100 ns at 50 K) and an ultrahigh carrier mobility, making it advantageous for spin-valleytronic applications.
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Affiliation(s)
- Junqing Xu
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, United States
| | - Hiroyuki Takenaka
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, United States
| | - Adela Habib
- Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, New York 12180, United States
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87544, United States
| | - Ravishankar Sundararaman
- Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, New York 12180, United States
| | - Yuan Ping
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, United States
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13
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Jiang B, Wang S, Sun J, Liu Z. Controllable Synthesis of Wafer-Scale Graphene Films: Challenges, Status, and Perspectives. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2008017. [PMID: 34106524 DOI: 10.1002/smll.202008017] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 02/22/2021] [Indexed: 06/12/2023]
Abstract
The availability of high-quality, large-scale, and single-crystal wafer-scale graphene films is fundamental for key device applications in the field of electronics, optics, and sensors. Synthesis determines the future: unleashing the full potentials of such emerging materials relies heavily upon their tailored synthesis in a scalable fashion, which is by no means an easy task to date. This review covers the state-of-the-art progress in the synthesis of wafer-scale graphene films by virtue of chemical vapor deposition (CVD), with a focus on main challenges and present status. Particularly, prevailing synthetic strategies are highlighted on a basis of the discussion in the reaction kinetics and gas-phase dynamics during CVD process. Perspectives with respect to key opportunities and promising research directions are proposed to guide the future development of wafer-scale graphene films.
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Affiliation(s)
- Bei Jiang
- Center for Nanochemistry (CNC), Beijing Science and Engineering Center for Nanocarbons, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, P. R. China
| | - Shiwei Wang
- Center for Nanochemistry (CNC), Beijing Science and Engineering Center for Nanocarbons, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, P. R. China
| | - Jingyu Sun
- College of Energy, Soochow Institute for Energy and Materials InnovationS (SIEMIS), Key Laboratory of Advanced Carbon Materials and Wearable Energy Technologies of Jiangsu Province, Soochow University, Suzhou, 215006, P. R. China
- Beijing Graphene Institute (BGI), Beijing, 100095, P. R. China
| | - Zhongfan Liu
- Center for Nanochemistry (CNC), Beijing Science and Engineering Center for Nanocarbons, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, P. R. China
- Beijing Graphene Institute (BGI), Beijing, 100095, P. R. China
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14
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Panda SN, Majumder S, Choudhury S, Bhattacharya A, Sinha S, Barman A. Femtosecond laser-induced spin dynamics in single-layer graphene/CoFeB thin films. NANOSCALE 2021; 13:13709-13718. [PMID: 34477646 DOI: 10.1039/d1nr03397b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Graphene/ferromagnet hybrid heterostructures are important building blocks of spintronics due to the unique ability of graphene to transport spin current over unprecedented distances and possible increase in its spin-orbit coupling due to proximity and hybridization. Here, we present magnetization dynamics over a femtosecond to nanosecond timescale by employing an all-optical time-resolved magneto-optical Kerr effect technique in single-layer graphene (SLG)/CoFeB thin films with varying CoFeB thickness and compared them with reference CoFeB thin films without an SLG underlayer. Gilbert damping variation with CoFeB thickness is modelled to extract spin-mixing conductance for the SLG/CoFeB interface and isolate the two-magnon scattering contribution from spin pumping. In SLG/CoFeB, we have established an inverse relationship between ultrafast demagnetization time (τm) and the Gilbert damping parameter (α) induced by interfacial spin accumulation and pure spin-current transport via a spin pumping mechanism. This systematic study of ultrafast demagnetization in SLG/CoFeB heterostructures and its connection with magnetic damping can help to design graphene-based ultrahigh-speed spintronic devices.
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Affiliation(s)
- Surya Narayan Panda
- Department of Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector-III, Salt Lake, Kolkata 700 106, India.
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15
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Sierra JF, Fabian J, Kawakami RK, Roche S, Valenzuela SO. Van der Waals heterostructures for spintronics and opto-spintronics. NATURE NANOTECHNOLOGY 2021; 16:856-868. [PMID: 34282312 DOI: 10.1038/s41565-021-00936-x] [Citation(s) in RCA: 116] [Impact Index Per Article: 38.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 06/03/2021] [Indexed: 06/13/2023]
Abstract
The large variety of 2D materials and their co-integration in van der Waals heterostructures enable innovative device engineering. In addition, their atomically thin nature promotes the design of artificial materials by proximity effects that originate from short-range interactions. Such a designer approach is particularly compelling for spintronics, which typically harnesses functionalities from thin layers of magnetic and non-magnetic materials and the interfaces between them. Here we provide an overview of recent progress in 2D spintronics and opto-spintronics using van der Waals heterostructures. After an introduction to the forefront of spin transport research, we highlight the unique spin-related phenomena arising from spin-orbit and magnetic proximity effects. We further describe the ability to create multifunctional hybrid heterostructures based on van der Waals materials, combining spin, valley and excitonic degrees of freedom. We end with an outlook on perspectives and challenges for the design and production of ultracompact all-2D spin devices and their potential applications in conventional and quantum technologies.
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Affiliation(s)
- Juan F Sierra
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain.
| | - Jaroslav Fabian
- Institute for Theoretical Physics, University of Regensburg, Regensburg, Germany
| | | | - Stephan Roche
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
| | - Sergio O Valenzuela
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain.
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain.
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16
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Muscas G, Jönsson PE, Serrano IG, Vallin Ö, Kamalakar MV. Ultralow magnetostrictive flexible ferromagnetic nanowires. NANOSCALE 2021; 13:6043-6052. [PMID: 33885602 DOI: 10.1039/d0nr08355k] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The integration of magneto-electric and spintronic sensors to flexible electronics presents a huge potential for advancing flexible and wearable technologies. Magnetic nanowires are core components for building such devices. Therefore, realizing flexible magnetic nanowires with engineered magneto-elastic properties is key to flexible spintronic circuits, as well as creating unique pathways to explore complex flexible spintronic, magnonic, and magneto-plasmonic devices. Here, we demonstrate highly resilient flexible ferromagnetic nanowires on transparent flexible substrates for the first time. Through extensive magneto-optical Kerr experiments, exploring the Villari effect, we reveal an ultralow magnetostrictive constant in nanowires, a two-order reduced value compared to bulk values. In addition, the flexible magnetic nanowires exhibit remarkable resilience sustaining bending radii ∼5 mm, high endurance, and enhanced elastic limit compared to thin films of similar thickness and composition. The observed performance is corroborated by our micro-magnetic simulations and can be attributed to the reduced size and strong nanostructure-interfacial effects. Such stable magnetic nanowires with ultralow magnetostriction open up new opportunities for stable surface mountable and wearable spintronic sensors, advanced nanospintronic circuits, and for exploring novel strain-induced quantum effects in hybrid devices.
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Affiliation(s)
- Giuseppe Muscas
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden.
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17
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Nieman R, Aquino AJA, Lischka H. Exploration of Graphene Defect Reactivity toward a Hydrogen Radical Utilizing a Preactivated Circumcoronene Model. J Phys Chem A 2021; 125:1152-1165. [PMID: 33507752 DOI: 10.1021/acs.jpca.0c09255] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
A preexisting chemisorbed defect is well-known to increase the reactivity of graphene which is normally chemically inert. Specifically, the presence of chemisorbed hydrogen atoms forming an sp3-hybridized C-H bond is known to increase the reactivity of neighboring carbon atoms toward additional hydrogenation with wide-ranging applications from materials science to astrochemistry. In this work, static DFT and DFT-based direct dynamics simulations are used to characterize the reactivity of a graphene sheet around an existing C-H bond defect. The spin density landscape shows how to guide subsequent H atom additions, always bonding most strongly to the carbon atom with greatest spin density. Molecular dynamics of an impinging H atom under thermal conditions with defect graphene was used to determine the statistics of probable reactions. The most frequent outcome is inelastic scattering (48%) and then Eley-Rideal (ER) abstraction of the chemisorbed H atom as vibrationally hot H2 (40%), while the least likely, but probably most interesting, result is formation of a novel C-H bond (12%). The C-H bonds always form in the β sublattice. The carbon atom in the para position shows to be most reactive toward the incoming H atom, followed by the ortho carbon, in agreement with the spin density computed in the static calculations. Globally, the graphene energy surface is repulsive, but the defects create local channels into this energy surface through which reactants can move locally through and react with the activated surface without a barrier.
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Affiliation(s)
- Reed Nieman
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409-1061, United States.,Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - Adelia J A Aquino
- Department of Mechanical Engineering, Texas Tech University, Lubbock, Texas 79409, United States.,School of Pharmaceutical Sciences and Technology, Tianjin University, Tianjin 300072, P. R. China
| | - Hans Lischka
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409-1061, United States.,School of Pharmaceutical Sciences and Technology, Tianjin University, Tianjin 300072, P. R. China
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18
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Zhao S, Li X, Dong B, Wang H, Wang H, Zhang Y, Han Z, Zhang H. Valley manipulation in monolayer transition metal dichalcogenides and their hybrid systems: status and challenges. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2021; 84:026401. [PMID: 33440363 DOI: 10.1088/1361-6633/abdb98] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Recently, the emerging conceptual valley-related devices have attracted much attention due to the progress on generating, controlling, and detecting the valley degree of freedom in the transition metal dichalcogenide (TMD) monolayers. In general, it is known that achieving valley degree of freedom with long valley lifetime is crucial in the implementation of valleytronic devices. Here, we provide a brief introduction of the basic understandings of valley degree of freedom. We as well review the recent experimental advancement in the modulation of valley degree of freedom. The strategies include optical/magnetic/electric field tuning, moiré patterns, plasmonic metasurface, defects and strain engineering. In addition, we summarize the corresponding mechanisms, which can help to obtain large degree of polarization and long valley lifetimes in monolayer TMDs. Based on these methods, two-dimensional valley-optoelectronic systems based on TMD heterostructures can be constructed, providing opportunities for such as the new paradigm in data processing and transmission. Challenges and perspectives on the development of valleytronics are highlighted as well.
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Affiliation(s)
- Siwen Zhao
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education, Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen 518060, People's Republic of China
- College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, People's Republic of China
| | - Xiaoxi Li
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, People's Republic of China
- School of Material Science and Engineering, University of Science and Technology of China, Hefei 230026, People's Republic of China
| | - Baojuan Dong
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan 030006, People's Republic of China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, People's Republic of China
| | - Huide Wang
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education, Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen 518060, People's Republic of China
| | - Hanwen Wang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, People's Republic of China
- School of Material Science and Engineering, University of Science and Technology of China, Hefei 230026, People's Republic of China
| | - Yupeng Zhang
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education, Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen 518060, People's Republic of China
| | - Zheng Han
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan 030006, People's Republic of China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, People's Republic of China
| | - Han Zhang
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education, Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen 518060, People's Republic of China
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19
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Khokhriakov D, Karpiak B, Hoque AM, Zhao B, Parui S, Dash SP. Robust Spin Interconnect with Isotropic Spin Dynamics in Chemical Vapor Deposited Graphene Layers and Boundaries. ACS NANO 2020; 14:15864-15873. [PMID: 33136363 PMCID: PMC7690053 DOI: 10.1021/acsnano.0c07163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 10/20/2020] [Indexed: 06/11/2023]
Abstract
The utilization of large-area graphene grown by chemical vapor deposition (CVD) is crucial for the development of scalable spin interconnects in all-spin-based memory and logic circuits. However, the fundamental influence of the presence of multilayer graphene patches and their boundaries on spin dynamics has not been addressed yet, which is necessary for basic understanding and application of robust spin interconnects. Here, we report universal spin transport and dynamic properties in specially devised single layer, bilayer, and trilayer graphene channels and their layer boundaries and folds that are usually present in CVD graphene samples. We observe uniform spin lifetime with isotropic spin relaxation for spins with different orientations in graphene layers and their boundaries at room temperature. In all of the inhomogeneous graphene channels, the spin lifetime anisotropy ratios for spins polarized out-of-plane and in-plane are measured to be close to unity. Our analysis shows the importance of both Elliott-Yafet and D'yakonov-Perel' mechanisms with an increasing role of the latter mechanism in multilayer channels. These results of universal and isotropic spin transport on large-area inhomogeneous CVD graphene with multilayer patches and their boundaries and folds at room temperature prove its outstanding spin interconnect functionality, which is beneficial for the development of scalable spintronic circuits.
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Affiliation(s)
- Dmitrii Khokhriakov
- Department
of Microtechnology and Nanoscience, Chalmers
University of Technology, SE-41296, Göteborg, Sweden
| | - Bogdan Karpiak
- Department
of Microtechnology and Nanoscience, Chalmers
University of Technology, SE-41296, Göteborg, Sweden
| | - Anamul Md. Hoque
- Department
of Microtechnology and Nanoscience, Chalmers
University of Technology, SE-41296, Göteborg, Sweden
| | - Bing Zhao
- Department
of Microtechnology and Nanoscience, Chalmers
University of Technology, SE-41296, Göteborg, Sweden
| | | | - Saroj P. Dash
- 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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20
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Panda J, Ramu M, Karis O, Sarkar T, Kamalakar MV. Ultimate Spin Currents in Commercial Chemical Vapor Deposited Graphene. ACS NANO 2020; 14:12771-12780. [PMID: 32945650 PMCID: PMC7596785 DOI: 10.1021/acsnano.0c03376] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 09/18/2020] [Indexed: 06/01/2023]
Abstract
Establishing ultimate spin current efficiency in graphene over industry-standard substrates can facilitate research and development exploration of spin current functions and spin sensing. At the same time, it can resolve core issues in spin relaxation physics while addressing the skepticism of graphene's practicality for planar spintronic applications. In this work, we reveal an exceptionally long spin communication capability of 45 μm and highest to date spin diffusion length of 13.6 μm in graphene on SiO2/Si at room temperature. Employing commercial chemical vapor deposited (CVD) graphene, we show how contact-induced surface charge transfer doping and device doping contributions, as well as spin relaxation, can be quenched in extremely long spin channels and thereby enable unexpectedly long spin diffusion lengths in polycrystalline CVD graphene. Extensive experiments show enhanced spin transport and precession in multiple longest channels (36 and 45 μm) that reveal the highest spin lifetime of ∼2.5-3.5 ns in graphene over SiO2/Si, even under ambient conditions. Such performance, made possible due to our devices approaching the intrinsic spin-orbit coupling of ∼20 μeV in graphene, reveals the role of the D'yakonov-Perel' spin relaxation mechanism in graphene channels as well as contact regions. Our record demonstration, fresh device engineering, and spin relaxation insights unlock the ultimate spin current capabilities of graphene on SiO2/Si, while the robust high performance of commercial CVD graphene can proliferate research and development of innovative spin sensors and spin computing circuits.
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Affiliation(s)
- J. Panda
- Department
of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
| | - M. Ramu
- Department
of Materials Science and Engineering, Uppsala
University, Box 35, SE-751 03 Uppsala, Sweden
| | - Olof Karis
- Department
of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
| | - Tapati Sarkar
- Department
of Materials Science and Engineering, Uppsala
University, Box 35, SE-751 03 Uppsala, Sweden
| | - M. Venkata Kamalakar
- Department
of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
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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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Serrano IG, Panda J, Edvinsson T, Kamalakar MV. Flexible transparent graphene laminates via direct lamination of graphene onto polyethylene naphthalate substrates. NANOSCALE ADVANCES 2020; 2:3156-3163. [PMID: 36134291 PMCID: PMC9416925 DOI: 10.1039/d0na00046a] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 06/08/2020] [Indexed: 05/31/2023]
Abstract
Graphene, with its excellent electrical, mechanical, and optical properties, has emerged as an exceptional material for flexible and transparent nanoelectronics. Such versatility makes it compelling to find new pathways to lay graphene sheets onto smooth, flexible substrates to create large-scale flexible transparent graphene conductors. Here, we report the realization of flexible transparent graphene laminates by direct adhesion of chemical vapor deposition (CVD) graphene on a polyethylene naphthalate (PEN) substrate, which is an emerging standard for flexible electronics. By systematically optimizing the conditions of a hot-press technique, we have identified that applying optimum temperature and pressure can make graphene directly adhere to flexible PEN substrates without any intermediate layer. The resultant flexible graphene films are transparent, have a standard sheet resistance of 1 kΩ with high bending resilience, and high optical transmittance of 85%. Our direct hot-press method is achieved below the glass transition temperature of the PEN substrate. Furthermore, we demonstrate press-assisted embossing for patterned transfer of graphene, and hence it can serve as a reliable new means for creating universal, transparent conducting patterned films for designing flexible nanoelectronic and optoelectronic components.
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Affiliation(s)
- Ismael G Serrano
- Department of Physics and Astronomy, Uppsala University Box 516 SE-751 20 Uppsala Sweden
| | - J Panda
- Department of Physics and Astronomy, Uppsala University Box 516 SE-751 20 Uppsala Sweden
| | - Tomas Edvinsson
- Department of Materials Science and Engineering, Uppsala University Box 534 SE-751 21 Uppsala Sweden
| | - M Venkata Kamalakar
- Department of Physics and Astronomy, Uppsala University Box 516 SE-751 20 Uppsala Sweden
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23
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Bonnet R, Martin P, Suffit S, Lafarge P, Lherbier A, Charlier JC, Della Rocca ML, Barraud C. Giant spin signals in chemically functionalized multiwall carbon nanotubes. SCIENCE ADVANCES 2020; 6:eaba5494. [PMID: 32789172 PMCID: PMC7399653 DOI: 10.1126/sciadv.aba5494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 06/17/2020] [Indexed: 06/11/2023]
Abstract
Transporting quantum information such as the spin information over micrometric or even millimetric distances is a strong requirement for the next-generation electronic circuits such as low-voltage spin-logic devices. This crucial step of transportation remains delicate in nontopologically protected systems because of the volatile nature of spin states. Here, a beneficial combination of different phenomena is used to approach this sought-after milestone for the beyond-Complementary Metal Oxide Semiconductor (CMOS) technology roadmap. First, a strongly spin-polarized charge current is injected using highly spin-polarized hybridized states emerging at the complex ferromagnetic metal/molecule interfaces. Second, the spin information is brought toward the conducting inner shells of a multiwall carbon nanotube used as a confined nanoguide benefiting from both weak spin-orbit and hyperfine interactions. The spin information is finally electrically converted because of a strong magnetoresistive effect. The experimental results are also supported by calculations qualitatively revealing exceptional spin transport properties of this system.
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Affiliation(s)
- Roméo Bonnet
- Université de Paris, Laboratoire Matériaux et Phénomènes Quantiques, CNRS, UMR 7162, 75013 Paris, France
| | - Pascal Martin
- Université de Paris, ITODYS, CNRS, UMR 7086, 75013 Paris, France
| | - Stéphan Suffit
- Université de Paris, Laboratoire Matériaux et Phénomènes Quantiques, CNRS, UMR 7162, 75013 Paris, France
| | - Philippe Lafarge
- Université de Paris, Laboratoire Matériaux et Phénomènes Quantiques, CNRS, UMR 7162, 75013 Paris, France
| | - Aurélien Lherbier
- Institute of Condensed Matter and Nanosciences (IMCN), Université catholique de Louvain (UCLouvain), B-1348 Louvain-la-Neuve, Belgium
| | - Jean-Christophe Charlier
- Institute of Condensed Matter and Nanosciences (IMCN), Université catholique de Louvain (UCLouvain), B-1348 Louvain-la-Neuve, Belgium
| | - Maria Luisa Della Rocca
- Université de Paris, Laboratoire Matériaux et Phénomènes Quantiques, CNRS, UMR 7162, 75013 Paris, France
| | - Clément Barraud
- Université de Paris, Laboratoire Matériaux et Phénomènes Quantiques, CNRS, UMR 7162, 75013 Paris, France
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24
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Zhang M, Wang X, Sun H, Wang N, He J, Wang N, Long Y, Huang C, Li Y. Induced Ferromagnetic Order of Graphdiyne Semiconductors by Introducing a Heteroatom. ACS CENTRAL SCIENCE 2020; 6:950-958. [PMID: 32607442 PMCID: PMC7318061 DOI: 10.1021/acscentsci.0c00348] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Indexed: 05/24/2023]
Abstract
To date, the realization of ferromagnetism in two-dimensional carbon semiconductors containing only sp electrons has remained a challenge for spintronics. Here, we utilize the atomic-level functionalization strategy to obtain three carbon matrix materials by accurately introducing different light elements (H, F, Cl) into graphdiyne's benzene ring. Their magnetic and conductive characteristics are thoroughly clarified via physical property measurements and DFT calculations. All of these carbon matrix materials retain their excellent intrinsic semiconductor properties. In particular, compared with the paramagnetism of HsGDY and ClsGDY, a robust ferromagnetic ordering as well as high mobility of up to 320 cm2 V-1 s-1 was observed in FsGDY, successfully realizing a ferromagnetic semiconductor. Through theory calculations, this unique ferromagnetic coupling can be attributed to the most striking charge transfer between carbon and fluorine atoms, demonstrating the advantages of controllable fabrication. These results not only reveal the important role of atomic-scale doping/substitution in optimizing graphdiyne material but also create new possibilities for manipulating spins and charges in 2D carbon materials.
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Affiliation(s)
- Mingjia Zhang
- Qingdao
Institute of Bioenergy and Bioprocess Technology, Chinese Academy
of Sciences, Qingdao 266101, P. R. China
| | - Xiaoxiong Wang
- College
of Physics, Qingdao University, Qingdao 266071, P. R. China
| | - Huijuan Sun
- College
of Physics, Qingdao University, Qingdao 266071, P. R. China
| | - Naiyin Wang
- Department
of Electronic Materials Engineering, Research School of Physics, The Australian National University, Canberra, Australian Capital
Territory 2601, Australia
| | - Jianjiang He
- Qingdao
Institute of Bioenergy and Bioprocess Technology, Chinese Academy
of Sciences, Qingdao 266101, P. R. China
| | - Ning Wang
- School of
Chemistry and Chemical Engineering, Shandong
University, Jinan 250100, P. R. China
| | - Yunze Long
- College
of Physics, Qingdao University, Qingdao 266071, P. R. China
| | - Changshui Huang
- Qingdao
Institute of Bioenergy and Bioprocess Technology, Chinese Academy
of Sciences, Qingdao 266101, P. R. China
- Center
of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Yuliang Li
- Beijing
National Laboratory for Molecular Sciences (BNLMS), CAS Key Laboratory
of Organic Solids, Institute of Chemistry,
Chinese Academy of Sciences, Beijing 100190, P. R. China
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25
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Nair AK, Rani S, Kamalakar MV, Ray SJ. Bi-stimuli assisted engineering and control of magnetic phase in monolayer CrOCl. Phys Chem Chem Phys 2020; 22:12806-12813. [PMID: 32469019 DOI: 10.1039/d0cp01204a] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Magnetic phase control and room temperature magnetic stability in two-dimensional (2D) materials are indispensable for realising advanced spintronic and magneto-electronic functions. Our current work employs first-principles calculations to comprehensively study the magnetic behaviour of 2D CrOCl, uncovering the impact of strain and electric field on the material. Our studies have revealed that uniaxial strain leads to the feasibility of room temperature ferromagnetism in the layer and also detected the occurrence of a ferromagnetic → antiferromagnetic phase transition in the system, which is anisotropic along the armchair and zigzag directions. Beyond such a strain effect, the coupling of strain and electric field leads to a remarkable enhancement of the Curie temperature (Tc) ∼ 450 K in CrOCl. These predictions based on our detailed simulations show the prospect of multi-stimuli magnetic phase control, which could have great significance for realizing magneto-mechanical sensors.
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Affiliation(s)
- A K Nair
- Department of Physics, Indian Institute of Technology Patna, Bihta 801106, India.
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26
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Cavill SA, Huang C, Offidani M, Lin YH, Cazalilla MA, Ferreira A. Proposal for Unambiguous Electrical Detection of Spin-Charge Conversion in Lateral Spin Valves. PHYSICAL REVIEW LETTERS 2020; 124:236803. [PMID: 32603148 DOI: 10.1103/physrevlett.124.236803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 03/09/2020] [Accepted: 05/12/2020] [Indexed: 06/11/2023]
Abstract
Efficient detection of spin-charge conversion is crucial for advancing our understanding of emergent phenomena in spin-orbit-coupled nanostructures. Here, we provide a proof of principle of an electrical detection scheme of spin-charge conversion that enables full disentanglement of competing spin-orbit coupling (SOC) transport phenomena in diffusive lateral channels, i.e., the inverse spin Hall effect and the spin galvanic effect. A suitable geometry in an applied oblique magnetic field is shown to provide direct access to SOC transport coefficients through a symmetry analysis of the output nonlocal resistance. The scheme is robust against tilting of the spin-injector magnetization, disorder, and spurious non-spin-related contributions to the nonlocal signal and can be used to probe spin-charge conversion effects in both spin-valve and hybrid optospintronic devices.
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Affiliation(s)
- Stuart A Cavill
- Department of Physics, University of York, YO10 5DD York, United Kingdom
| | - Chunli Huang
- Department of Physics, National Tsing Hua University and National Center for Theoretical Sciences (NCTS), Hsinchu 30013, Taiwan
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Manuel Offidani
- Department of Physics, University of York, YO10 5DD York, United Kingdom
| | - Yu-Hsuan Lin
- Department of Physics, National Tsing Hua University and National Center for Theoretical Sciences (NCTS), Hsinchu 30013, Taiwan
| | - Miguel A Cazalilla
- Department of Physics, National Tsing Hua University and National Center for Theoretical Sciences (NCTS), Hsinchu 30013, Taiwan
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal, 4, 20018 Donostia, Spain
- Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502, Japan
| | - Aires Ferreira
- Department of Physics, University of York, YO10 5DD York, United Kingdom
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27
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Vila M, Garcia JH, Cummings AW, Power SR, Groth CW, Waintal X, Roche S. Nonlocal Spin Dynamics in the Crossover from Diffusive to Ballistic Transport. PHYSICAL REVIEW LETTERS 2020; 124:196602. [PMID: 32469541 DOI: 10.1103/physrevlett.124.196602] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 04/27/2020] [Indexed: 06/11/2023]
Abstract
Improved fabrication techniques have enabled the possibility of ballistic transport and unprecedented spin manipulation in ultraclean graphene devices. Spin transport in graphene is typically probed in a nonlocal spin valve and is analyzed using spin diffusion theory, but this theory is not necessarily applicable when charge transport becomes ballistic or when the spin diffusion length is exceptionally long. Here, we study these regimes by performing quantum simulations of graphene nonlocal spin valves. We find that conventional spin diffusion theory fails to capture the crossover to the ballistic regime as well as the limit of long spin diffusion length. We show that the latter can be described by an extension of the current theoretical framework. Finally, by covering the whole range of spin dynamics, our study opens a new perspective to predict and scrutinize spin transport in graphene and other two-dimensional material-based ultraclean devices.
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Affiliation(s)
- Marc Vila
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Spain
- Department of Physics, Universitat Autònoma de Barcelona, Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Jose H Garcia
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Aron W Cummings
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Stephen R Power
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Spain
- Universitat Autònoma de Barcelona, Campus UAB, Bellaterra, 08193 Barcelona, Spain
- School of Physics, Trinity College Dublin, Dublin 2, Ireland
| | - Christoph W Groth
- Université Grenoble Alpes, CEA, IRIG-PHELIQS, 38000 Grenoble, France
| | - Xavier Waintal
- Université Grenoble Alpes, CEA, IRIG-PHELIQS, 38000 Grenoble, France
| | - Stephan Roche
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Spain
- ICREA-Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain
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28
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Kumari P, Majumder S, Rani S, Nair AK, Kumari K, Kamalakar MV, Ray SJ. High efficiency spin filtering in magnetic phosphorene. Phys Chem Chem Phys 2020; 22:5893-5901. [DOI: 10.1039/c9cp05390e] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We present high efficiency spin filtering behaviour in magnetically rendered phosphorene, doped with various 3d block elements. A phase diagram was obtained depicting the presence of various electronic and magnetic states.
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Affiliation(s)
- P. Kumari
- Department of Physics
- Indian Institute of Technology Patna
- Bihta 801106
- India
| | - S. Majumder
- Department of Physics
- Indian Institute of Technology Patna
- Bihta 801106
- India
| | - S. Rani
- Department of Physics
- Indian Institute of Technology Patna
- Bihta 801106
- India
| | - A. K. Nair
- Department of Physics
- Indian Institute of Technology Patna
- Bihta 801106
- India
| | - K. Kumari
- Department of Physics
- Indian Institute of Technology Patna
- Bihta 801106
- India
| | | | - S. J. Ray
- Department of Physics
- Indian Institute of Technology Patna
- Bihta 801106
- India
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29
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Anomalous Non-Linear to Linear Shift in Magnetoresistance of Amorphous Carbon Films. CRYSTALS 2019. [DOI: 10.3390/cryst9120618] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Non-linear to linear negative magnetoresistance (MR) was studied under the magnetic field ranging from −7 T to 7 T with a change in measurement temperature from 2 K to 300 K. Under the magnetic field of 7 T, a maximum MR magnitude of 8.2% was observed at 2 K. The chemical vapor deposition technique was adopted to synthesize the amorphous carbon thin films. Non-saturated and non-linear negative MR was observed for the lower temperatures, while 10 K was observed as transition temperature. Afterwards, the more likely linear MR behavior was observed up to 300 K. MR shape change was correlated with the structural morphology of metallic disordered graphitic layers or the random stacking of graphene layers with amorphous carbon. The negative MR mechanism for such a non-linear to linear shift was partially assumed as a combined effect of the diffused scattering theory and the weak localization theory. The negative MR effect has a direct relation with the degree of structural order.
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30
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Cummings AW, Dubois SMM, Charlier JC, Roche S. Universal Spin Diffusion Length in Polycrystalline Graphene. NANO LETTERS 2019; 19:7418-7426. [PMID: 31532994 DOI: 10.1021/acs.nanolett.9b03112] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Graphene grown by chemical vapor deposition (CVD) is the most promising material for industrial-scale applications based on graphene monolayers. It also holds promise for spintronics; despite being polycrystalline, spin transport in CVD graphene has been measured over lengths up to 30 μm, which is on par with the best measurements made in single-crystal graphene. These results suggest that grain boundaries (GBs) in CVD graphene, while impeding charge transport, may have little effect on spin transport. However, to date very little is known about the true impact of disordered networks of GBs on spin relaxation. Here, by using first-principles simulations, we derive an effective tight-binding model of graphene GBs in the presence of spin-orbit coupling (SOC), which we then use to evaluate spin transport in realistic morphologies of polycrystalline graphene. The spin diffusion length is found to be independent of the grain size, and it is determined only by the strength of the substrate-induced SOC. This result is consistent with the D'yakonov-Perel' mechanism of spin relaxation in the diffusive regime, but we find that it also holds in the presence of quantum interference. These results clarify the role played by GBs and demonstrate that the average grain size does not dictate the upper limit for spin transport in CVD-grown graphene, a result of fundamental importance for optimizing large-scale graphene-based spintronic devices.
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Affiliation(s)
- Aron W Cummings
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST , Campus UAB, Bellaterra , 08193 Barcelona , Spain
| | - Simon M-M Dubois
- Institute of Condensed Matter and Nanosciences , Université catholique de Louvain , B-1348 Louvain-la-Neuve , Belgium
| | - Jean-Christophe Charlier
- Institute of Condensed Matter and Nanosciences , Université catholique de Louvain , B-1348 Louvain-la-Neuve , Belgium
| | - Stephan Roche
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST , Campus UAB, Bellaterra , 08193 Barcelona , Spain
- ICREA-Institució Catalana de Recerca i Estudis Avançats , 08010 Barcelona , Spain
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31
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Liu Y, Zhang S, He J, Wang ZM, Liu Z. Recent Progress in the Fabrication, Properties, and Devices of Heterostructures Based on 2D Materials. NANO-MICRO LETTERS 2019; 11:13. [PMID: 34137973 PMCID: PMC7770868 DOI: 10.1007/s40820-019-0245-5] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 01/28/2019] [Indexed: 05/03/2023]
Abstract
With a large number of researches being conducted on two-dimensional (2D) materials, their unique properties in optics, electrics, mechanics, and magnetics have attracted increasing attention. Accordingly, the idea of combining distinct functional 2D materials into heterostructures naturally emerged that provides unprecedented platforms for exploring new physics that are not accessible in a single 2D material or 3D heterostructures. Along with the rapid development of controllable, scalable, and programmed synthesis techniques of high-quality 2D heterostructures, various heterostructure devices with extraordinary performance have been designed and fabricated, including tunneling transistors, photodetectors, and spintronic devices. In this review, we present a summary of the latest progresses in fabrications, properties, and applications of different types of 2D heterostructures, followed by the discussions on present challenges and perspectives of further investigations.
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Affiliation(s)
- Yanping Liu
- School of Physics and Electronics, Hunan Key Laboratory for Super-Microstructure and Ultrafast Process, Central South University, 932 South Lushan Road, Changsha, 410083, Hunan, People's Republic of China.
| | - Siyu Zhang
- School of Physics and Electronics, Hunan Key Laboratory for Super-Microstructure and Ultrafast Process, Central South University, 932 South Lushan Road, Changsha, 410083, Hunan, People's Republic of China
| | - Jun He
- School of Physics and Electronics, Hunan Key Laboratory for Super-Microstructure and Ultrafast Process, Central South University, 932 South Lushan Road, Changsha, 410083, Hunan, People's Republic of China
| | - Zhiming M Wang
- State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, People's Republic of China.
| | - Zongwen Liu
- School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, NSW, 2006, Australia.
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32
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Serrano IG, Panda J, Denoel F, Vallin Ö, Phuyal D, Karis O, Kamalakar MV. Two-Dimensional Flexible High Diffusive Spin Circuits. NANO LETTERS 2019; 19:666-673. [PMID: 30632370 DOI: 10.1021/acs.nanolett.8b03520] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Owing to their unprecedented electronic properties, graphene and two-dimensional (2D) crystals have brought fresh opportunities for advances in planar spintronic devices. Graphene is an ideal medium for spin transport while being an exceptionally resilient material for flexible nanoelectronics. However, these extraordinary traits have never been combined to create flexible graphene spin circuits. Realizing such circuits could lead to bendable strain-spin sensors, as well as a unique platform to explore pure spin current based operations and low-power 2D flexible nanoelectronics. Here, we demonstrate graphene spin circuits on flexible substrates for the first time. Despite the rough topography of the flexible substrates, these circuits prepared with chemical vapor deposited monolayer graphene reveal an efficient room temperature spin transport with distinctively large spin diffusion coefficients ∼0.2 m2 s-1. Compared to earlier graphene devices on Si/SiO2 substrates, such values are up to 20 times larger, leading to one order higher spin signals and an enhanced spin diffusion length ∼10 μm in graphene-based nonlocal spin valves fabricated using industry standard systems. This high performance arising out of a characteristic substrate terrain shows promise of a scalable and flexible platform towards flexible 2D spintronics. Our innovation is a key step for the exploration of strain-dependent 2D spin phenomena and paves the way for flexible graphene spin memory-logic units and planar spin sensors.
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Affiliation(s)
- I G Serrano
- Department of Physics and Astronomy , Uppsala University , Box 516, SE 751 20 , Uppsala , Sweden
| | - J Panda
- Department of Physics and Astronomy , Uppsala University , Box 516, SE 751 20 , Uppsala , Sweden
| | - Fernand Denoel
- Department of Physics and Astronomy , Uppsala University , Box 516, SE 751 20 , Uppsala , Sweden
| | - Örjan Vallin
- Department of Engineering Sciences , Uppsala University , Box 534, SE 751 21 , Uppsala , Sweden
| | - Dibya Phuyal
- Department of Physics and Astronomy , Uppsala University , Box 516, SE 751 20 , Uppsala , Sweden
| | - Olof Karis
- Department of Physics and Astronomy , Uppsala University , Box 516, SE 751 20 , Uppsala , Sweden
| | - M Venkata Kamalakar
- Department of Physics and Astronomy , Uppsala University , Box 516, SE 751 20 , Uppsala , Sweden
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33
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Safeer CK, Ingla-Aynés J, Herling F, Garcia JH, Vila M, Ontoso N, Calvo MR, Roche S, Hueso LE, Casanova F. Room-Temperature Spin Hall Effect in Graphene/MoS 2 van der Waals Heterostructures. NANO LETTERS 2019; 19:1074-1082. [PMID: 30608710 DOI: 10.1021/acs.nanolett.8b04368] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Graphene is an excellent material for long-distance spin transport but allows little spin manipulation. Transition-metal dichalcogenides imprint their strong spin-orbit coupling into graphene via the proximity effect, and it has been predicted that efficient spin-to-charge conversion due to spin Hall and Rashba-Edelstein effects could be achieved. Here, by combining Hall probes with ferromagnetic electrodes, we unambiguously demonstrate experimentally the spin Hall effect in graphene induced by MoS2 proximity and for varying temperatures up to room temperature. The fact that spin transport and the spin Hall effect occur in different parts of the same material gives rise to a hitherto unreported efficiency for the spin-to-charge voltage output. Additionally, for a single graphene/MoS2 heterostructure-based device, we evidence a superimposed spin-to-charge current conversion that can be indistinguishably associated with either the proximity-induced Rashba-Edelstein effect in graphene or the spin Hall effect in MoS2. By a comparison of our results to theoretical calculations, the latter scenario is found to be the most plausible one. Our findings pave the way toward the combination of spin information transport and spin-to-charge conversion in two-dimensional materials, opening exciting opportunities in a variety of future spintronic applications.
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Affiliation(s)
- C K Safeer
- 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
| | - José H Garcia
- Catalan Institute of Nanoscience and Nanotechnology (ICN2) , CSIC and The Barcelona Institute of Science and Technology , Campus UAB , 08193 Bellaterra , Catalonia , Spain
| | - Marc Vila
- Catalan Institute of Nanoscience and Nanotechnology (ICN2) , CSIC and The Barcelona Institute of Science and Technology , Campus UAB , 08193 Bellaterra , Catalonia , Spain
- Department of Physics , Universitat Autònoma de Barcelona , Campus UAB , 08193 Bellaterra , Catalonia , Spain
| | - Nerea Ontoso
- CIC nanoGUNE , 20018 Donostia-San Sebastian , 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
| | - Stephan Roche
- Catalan Institute of Nanoscience and Nanotechnology (ICN2) , CSIC and The Barcelona Institute of Science and Technology , Campus UAB , 08193 Bellaterra , Catalonia , Spain
- ICREA - Institució Catalana de Recerca i Estudis Avançats , 08010 Barcelona , Catalonia , Spain
| | - Luis E Hueso
- CIC nanoGUNE , 20018 Donostia-San Sebastian , Basque Country , Spain
- IKERBASQUE , Basque Foundation for Science , 48013 Bilbao , Basque Country , 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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34
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Nair AK, Kumari P, Kamalakar MV, Ray SJ. Dramatic magnetic phase designing in phosphorene. Phys Chem Chem Phys 2019; 21:23713-23719. [DOI: 10.1039/c9cp04871e] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Phosphorene is a unique two-dimensional semiconductor that has huge potential for nanoelectronic and spintronic applications. In the presence of various 3d block elements, remarkable feasibility of ferromagnetism and antiferromagnetism up to a large temperature ∼1150 K was observed.
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Affiliation(s)
- A. K. Nair
- Department of Physics
- Indian Institute of Technology Patna
- Bihta 801106
- India
| | - P. Kumari
- Department of Physics
- Indian Institute of Technology Patna
- Bihta 801106
- India
| | | | - S. J. Ray
- Department of Physics
- Indian Institute of Technology Patna
- Bihta 801106
- India
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35
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Afzal AM, Min KH, Ko BM, Eom J. Observation of giant spin–orbit interaction in graphene and heavy metal heterostructures. RSC Adv 2019; 9:31797-31805. [PMID: 35527934 PMCID: PMC9072641 DOI: 10.1039/c9ra06961e] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 10/01/2019] [Indexed: 11/21/2022] Open
Abstract
Graphene is a promising material demonstrating some interesting phenomena such as the spin Hall effect, bipolar transistor effect, and non-trivial topological states. However, graphene has an intrinsically small spin–orbit interaction (SOI), making it difficult to apply in spintronic devices. The electronic band structure of graphene makes it possible to develop a systematic method to enhance SOI extrinsically. In this study, we designed a graphene field-effect transistor with a Pb layer intercalated between graphene (Gr) and Au layers and studied the effect on the strength of the SOI. The SOI in our system was significantly increased to 80 meV, which led to a giant non-local signal (∼180 Ω) at room temperature due to the spin Hall effect. Further, we extract key parameters of spin transport from the length and width dependence of non-local measurement. To support these findings, we also measured the temperature and gate-dependent weak localization (WL) effect. We obtained the magnitude of the SOI and spin relaxation time of Gr via quantitative analysis of WL. The SOI magnitudes estimated from the non-local signal and the WL effect are close in value. The enhancement of the SOI of Gr at room temperature is a potential simple manipulation method to explore the use of this material for spin-based applications. We used Pb as an intercalated layer between the graphene and Au and measured the spin–orbit interaction in local and non-local measurement configurations.![]()
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Affiliation(s)
- Amir Muhammad Afzal
- Department of Physics & Astronomy
- Graphene Research Institute-Texas Photonics Center International Research Center (GRI-TPC IRC)
- Sejong University
- Seoul 05006
- Korea
| | - Kuen Hong Min
- Department of Physics & Astronomy
- Graphene Research Institute-Texas Photonics Center International Research Center (GRI-TPC IRC)
- Sejong University
- Seoul 05006
- Korea
| | - Byung Min Ko
- Department of Physics & Astronomy
- Graphene Research Institute-Texas Photonics Center International Research Center (GRI-TPC IRC)
- Sejong University
- Seoul 05006
- Korea
| | - Jonghwa Eom
- Department of Physics & Astronomy
- Graphene Research Institute-Texas Photonics Center International Research Center (GRI-TPC IRC)
- Sejong University
- Seoul 05006
- Korea
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36
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Rojas WY, Villegas CEP, Rocha AR. Spin-orbit coupling prevents spin channel suppression of transition metal atoms on armchair graphene nanoribbons. Phys Chem Chem Phys 2018; 20:29826-29832. [PMID: 30467570 DOI: 10.1039/c8cp05337e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We investigate the spin-dependent electronic and transport properties of armchair graphene nanoribbons including spin-orbit coupling due to the presence of nickel and iridium adatoms by using ab initio calculations within the spin-polarized density functional theory and non-equilibrium Green's function formalism. Our results indicate that the intensity of the spin-flip precession is a direct consequence of the relaxed adsorption sites of the adatoms. We point out that d orbitals of Ni and Ir result in strong dependence on the spin-conserved and spin-flip transmission probabilities. In particular, we show that the presence of spin-orbit coupling can lead to an enhancement of the transmission probabilities especially around resonances arising due to weak coupling with specific orbitals.
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Affiliation(s)
- W Y Rojas
- School of Electronic Engineering, Bangor University, Bangor LL57 1UT, UK
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37
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Mouafo LDN, Godel F, Melinte G, Hajjar-Garreau S, Majjad H, Dlubak B, Ersen O, Doudin B, Simon L, Seneor P, Dayen JF. Anisotropic Magneto-Coulomb Properties of 2D-0D Heterostructure Single Electron Device. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1802478. [PMID: 30084135 DOI: 10.1002/adma.201802478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 06/29/2018] [Indexed: 06/08/2023]
Abstract
Fabrication and spintronics properties of 2D-0D heterostructures are reported. Devices based on graphene ("Gr")-aluminium nanoclusters heterostructures show robust and reproducible single-electron transport features, in addition to spin-dependent functionality when using a top magnetic electrode. The magnetic orientation of this single ferromagnetic electrode enables the modulation of the environmental charge experienced by the aluminium nanoclusters. This anisotropic magneto-Coulomb effect, originating from spin-orbit coupling within the ferromagnetic electrode, provides tunable spin valve-like magnetoresistance signatures without the requirement of spin coherent charge tunneling. These results extend the capability of Gr to act both as electrode and as a platform for the growth of 2D-0D mixed-dimensional van der Waals heterostructures, providing magnetic functionalities in the Coulomb blockade regime on scalable spintronic devices. These heterostructures pave the way towards novel device architectures at the crossroads of 2D material physics and spin electronics.
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Affiliation(s)
- Louis Donald Notemgnou Mouafo
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), UMR 7504, F-67000, Strasbourg, France
| | - Florian Godel
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, 91767, Palaiseau, France
| | - Georgian Melinte
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), UMR 7504, F-67000, Strasbourg, France
| | - Samar Hajjar-Garreau
- Institut de Sciences des Matériaux de Mulhouse, CNRS-UMR 7361, Université de Haute Alsace, 3Bis, rue Alfred Werner, Mulhouse, 68093, France
| | - Hicham Majjad
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), UMR 7504, F-67000, Strasbourg, France
| | - Bruno Dlubak
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, 91767, Palaiseau, France
| | - Ovidiu Ersen
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), UMR 7504, F-67000, Strasbourg, France
| | - Bernard Doudin
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), UMR 7504, F-67000, Strasbourg, France
| | - Laurent Simon
- Institut de Sciences des Matériaux de Mulhouse, CNRS-UMR 7361, Université de Haute Alsace, 3Bis, rue Alfred Werner, Mulhouse, 68093, France
| | - Pierre Seneor
- Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, 91767, Palaiseau, France
| | - Jean-Francois Dayen
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), UMR 7504, F-67000, Strasbourg, France
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38
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Khokhriakov D, Cummings AW, Song K, Vila M, Karpiak B, Dankert A, Roche S, Dash SP. Tailoring emergent spin phenomena in Dirac material heterostructures. SCIENCE ADVANCES 2018; 4:eaat9349. [PMID: 30255150 PMCID: PMC6155095 DOI: 10.1126/sciadv.aat9349] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 08/09/2018] [Indexed: 06/01/2023]
Abstract
Dirac materials such as graphene and topological insulators (TIs) are known to have unique electronic and spintronic properties. We combine graphene with TIs in van der Waals heterostructures to demonstrate the emergence of a strong proximity-induced spin-orbit coupling in graphene. By performing spin transport and precession measurements supported by ab initio simulations, we discover a strong tunability and suppression of the spin signal and spin lifetime due to the hybridization of graphene and TI electronic bands. The enhanced spin-orbit coupling strength is estimated to be nearly an order of magnitude higher than in pristine graphene. These findings in graphene-TI heterostructures could open interesting opportunities for exploring exotic physical phenomena and new device functionalities governed by topological proximity effects.
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Affiliation(s)
- Dmitrii Khokhriakov
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296 Göteborg, Sweden
| | - Aron W. Cummings
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), Consejo Superior de Investigaciones Científicas (CSIC) and Barcelona Institute of Science and Technology (BIST), Campus Universitat Autònoma de Barcelona (UAB), Bellaterra, 08193 Barcelona, Spain
| | - Kenan Song
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), Consejo Superior de Investigaciones Científicas (CSIC) and Barcelona Institute of Science and Technology (BIST), Campus Universitat Autònoma de Barcelona (UAB), Bellaterra, 08193 Barcelona, Spain
- Universitat Autònoma de Barcelona, Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Marc Vila
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), Consejo Superior de Investigaciones Científicas (CSIC) and Barcelona Institute of Science and Technology (BIST), Campus Universitat Autònoma de Barcelona (UAB), Bellaterra, 08193 Barcelona, Spain
- Universitat Autònoma de Barcelona, Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Bogdan Karpiak
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296 Göteborg, Sweden
| | - André Dankert
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296 Göteborg, Sweden
| | - Stephan Roche
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), Consejo Superior de Investigaciones Científicas (CSIC) and Barcelona Institute of Science and Technology (BIST), Campus Universitat Autònoma de Barcelona (UAB), Bellaterra, 08193 Barcelona, Spain
- ICREA, Institució Catalana de Recerca i Estudis Avançats, 08070 Barcelona, Spain
| | - Saroj P. Dash
- 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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39
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Chan YJ, Huang CH, Chang YM, Lu YY, Wu SY, Wei DH, Kuo CC. Dipolar magnetism in assembled Co nanoparticles on graphene. Phys Chem Chem Phys 2018; 20:20629-20634. [PMID: 30059115 DOI: 10.1039/c8cp03145b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The magnetic properties of the assembled Co nanoparticles on graphene were studied using X-ray magnetic circular dichroism (XMCD), magneto-optical Kerr effects, and a modeling simulation. We demonstrate that the superparamagnetic nanoparticles reveal a ferromagnetic phase when they are assembled on graphene. The moderate increase of the XMCD asymmetry and magnetization with coverage for this assembly indicates a dipolar-mediated magnetism, which is further verified by a model simulation considering the dipolar interaction between neighboring nanoparticles. Furthermore, C K-edge spectra reveal visible dichroism at the π* state of graphene, which indicates the existence of a spin-polarized interface state, while the assembled Co nanoparticles reveal a ferromagnetic phase. These results suggest an efficient route to stabilize the ferromagnetic phase of nanostructures on graphene by tailoring dipolar interactions, which is essential to realize a higher efficiency of spin injection in graphene-based spintronics.
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Affiliation(s)
- Yao-Jui Chan
- Department of Physics, National Sun Yat-sen University, Kaohsiung 80424, Taiwan.
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40
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Bonfanti M, Achilli S, Martinazzo R. Sticking of atomic hydrogen on graphene. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:283002. [PMID: 29845971 DOI: 10.1088/1361-648x/aac89f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Recent years have witnessed an ever growing interest in the interactions between hydrogen atoms and a graphene sheet. Largely motivated by the possibility of modulating the electric, optical and magnetic properties of graphene, a huge number of studies have appeared recently that added to and enlarged earlier investigations on graphite and other carbon materials. In this review we give a glimpse of the many facets of this adsorption process, as they emerged from these studies. The focus is on those issues that have been addressed in detail, under carefully controlled conditions, with an emphasis on the interplay between the adatom structures, their formation dynamics and the electric, magnetic and chemical properties of the carbon sheet.
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Affiliation(s)
- Matteo Bonfanti
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, Max-von-Laue-Str. 7, 60438 Frankfurt, Germany
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41
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Garcia JH, Vila M, Cummings AW, Roche S. Spin transport in graphene/transition metal dichalcogenide heterostructures. Chem Soc Rev 2018; 47:3359-3379. [DOI: 10.1039/c7cs00864c] [Citation(s) in RCA: 112] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
This review summarizes the theoretical and experimental studies of spin transport in graphene interfaced with transition metal dichalcogenides, and assesses its potential for future spintronic applications.
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Affiliation(s)
- Jose H. Garcia
- Catalan Institute of Nanoscience and Nanotechnology (ICN2)
- CSIC and BIST
- 08193 Barcelona
- Spain
| | - Marc Vila
- Catalan Institute of Nanoscience and Nanotechnology (ICN2)
- CSIC and BIST
- 08193 Barcelona
- Spain
- Department of Physics
| | - Aron W. Cummings
- Catalan Institute of Nanoscience and Nanotechnology (ICN2)
- CSIC and BIST
- 08193 Barcelona
- Spain
| | - Stephan Roche
- Catalan Institute of Nanoscience and Nanotechnology (ICN2)
- CSIC and BIST
- 08193 Barcelona
- Spain
- ICREA – Institució Catalana de Recerca i Estudis Avançats
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42
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Scale-invariant large nonlocality in polycrystalline graphene. Nat Commun 2017; 8:2198. [PMID: 29259177 PMCID: PMC5736749 DOI: 10.1038/s41467-017-02346-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 11/22/2017] [Indexed: 11/08/2022] Open
Abstract
The observation of large nonlocal resistances near the Dirac point in graphene has been related to a variety of intrinsic Hall effects, where the spin or valley degrees of freedom are controlled by symmetry breaking mechanisms. Engineering strong spin or valley Hall signals on scalable graphene devices could stimulate further practical developments of spin- and valleytronics. Here we report on scale-invariant nonlocal transport in large-scale chemical vapor deposition graphene under an applied external magnetic field. Contrary to previously reported Zeeman spin Hall effect, our results are explained by field-induced spin-filtered edge states whose sensitivity to grain boundaries manifests in the nonlocal resistance. This phenomenon, related to the emergence of the quantum Hall regime, persists up to the millimeter scale, showing that polycrystalline morphology can be imprinted in nonlocal transport. This suggests that topological Hall effects in large-scale graphene materials are highly sensitive to the underlying structural morphology, limiting practical realizations.
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43
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Singh S, Katoch J, Zhu T, Wu RJ, Ahmed AS, Amamou W, Wang D, Mkhoyan KA, Kawakami RK. Strontium Oxide Tunnel Barriers for High Quality Spin Transport and Large Spin Accumulation in Graphene. NANO LETTERS 2017; 17:7578-7585. [PMID: 29129075 DOI: 10.1021/acs.nanolett.7b03543] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The quality of the tunnel barrier at the ferromagnet/graphene interface plays a pivotal role in graphene spin valves by circumventing the impedance mismatch problem, decreasing interfacial spin dephasing mechanisms and decreasing spin absorption back into the ferromagnet. It is thus crucial to integrate superior tunnel barriers to enhance spin transport and spin accumulation in graphene. Here, we employ a novel tunnel barrier, strontium oxide (SrO), onto graphene to realize high quality spin transport as evidenced by room-temperature spin relaxation times exceeding a nanosecond in graphene on silicon dioxide substrates. Furthermore, the smooth and pinhole-free SrO tunnel barrier grown by molecular beam epitaxy (MBE), which can withstand large charge injection current densities, allows us to experimentally realize large spin accumulation in graphene at room temperature. This work puts graphene on the path to achieve efficient manipulation of nanomagnet magnetization using spin currents in graphene for logic and memory applications.
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Affiliation(s)
- Simranjeet Singh
- Department of Physics, The Ohio State University , Columbus, Ohio 43210, United States
| | - Jyoti Katoch
- Department of Physics, The Ohio State University , Columbus, Ohio 43210, United States
| | - Tiancong Zhu
- Department of Physics, The Ohio State University , Columbus, Ohio 43210, United States
| | - Ryan J Wu
- Department of Chemical Engineering and Materials Science, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Adam S Ahmed
- Department of Physics, The Ohio State University , Columbus, Ohio 43210, United States
| | - Walid Amamou
- Program of Materials Science and Engineering, University of California , Riverside, California 92521, United States
| | - Dongying Wang
- Department of Physics, The Ohio State University , Columbus, Ohio 43210, United States
| | - K Andre Mkhoyan
- Department of Chemical Engineering and Materials Science, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Roland K Kawakami
- Department of Physics, The Ohio State University , Columbus, Ohio 43210, United States
- Program of Materials Science and Engineering, University of California , Riverside, California 92521, United States
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44
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Cummings AW, Garcia JH, Fabian J, Roche S. Giant Spin Lifetime Anisotropy in Graphene Induced by Proximity Effects. PHYSICAL REVIEW LETTERS 2017; 119:206601. [PMID: 29219336 DOI: 10.1103/physrevlett.119.206601] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Indexed: 06/07/2023]
Abstract
We report on fundamental aspects of spin dynamics in heterostructures of graphene and transition metal dichalcogenides (TMDCs). By using realistic models derived from first principles we compute the spin lifetime anisotropy, defined as the ratio of lifetimes for spins pointing out of the graphene plane to those pointing in the plane. We find that the anisotropy can reach values of tens to hundreds, which is unprecedented for typical 2D systems with spin-orbit coupling and indicates a qualitatively new regime of spin relaxation. This behavior is mediated by spin-valley locking, which is strongly imprinted onto graphene by TMDCs. Our results indicate that this giant spin lifetime anisotropy can serve as an experimental signature of materials with strong spin-valley locking, including graphene-TMDC heterostructures and TMDCs themselves. Additionally, materials with giant spin lifetime anisotropy can provide an exciting platform for manipulating the valley and spin degrees of freedom, and for designing novel spintronic devices.
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Affiliation(s)
- Aron W Cummings
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Jose H Garcia
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Jaroslav Fabian
- Insitute for Theoretical Physics, University of Regensburg, 93040 Regensburg, Germany
| | - Stephan Roche
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Spain
- ICREA, Institució Catalana de Recerca i Estudis Avançats, 08070 Barcelona, Spain
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45
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Dankert A, Karpiak B, Dash SP. Hall sensors batch-fabricated on all-CVD h-BN/graphene/h-BN heterostructures. Sci Rep 2017; 7:15231. [PMID: 29123124 PMCID: PMC5680335 DOI: 10.1038/s41598-017-12277-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 09/06/2017] [Indexed: 11/09/2022] Open
Abstract
The two-dimensional (2D) material graphene is highly promising for Hall sensors due to its potential of having high charge carrier mobility and low carrier concentration at room temperature. Here, we report the scalable batch-fabrication of magnetic Hall sensors on graphene encapsulated in hexagonal boron nitride (h-BN) using commercially available large area CVD grown materials. The all-CVD grown h-BN/graphene/h-BN van der Waals heterostructures were prepared by layer transfer technique and Hall sensors were batch-fabricated with 1D edge metal contacts. The current-related Hall sensitivities up to 97 V/AT are measured at room temperature. The Hall sensors showed robust performance over the wafer scale with stable characteristics over six months in ambient environment. This work opens avenues for further development of growth and fabrication technologies of all-CVD 2D material heterostructures and allows further improvements in Hall sensor performance for practical applications.
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Affiliation(s)
- André Dankert
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296, Göteborg, Sweden.
| | - Bogdan Karpiak
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296, Göteborg, Sweden
| | - Saroj P Dash
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296, Göteborg, Sweden.
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46
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Large room temperature spin-to-charge conversion signals in a few-layer graphene/Pt lateral heterostructure. Nat Commun 2017; 8:661. [PMID: 28939841 PMCID: PMC5610249 DOI: 10.1038/s41467-017-00563-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 07/10/2017] [Indexed: 11/15/2022] Open
Abstract
Electrical generation and detection of pure spin currents without the need of magnetic materials are key elements for the realization of full electrically controlled spintronic devices. In this framework, achieving a large spin-to-charge conversion signal is crucial, as considerable outputs are needed for plausible applications. Unfortunately, the values obtained so far have been rather low. Here we exploit the spin Hall effect by using Pt, a non-magnetic metal with strong spin-orbit coupling, to generate and detect pure spin currents in a few-layer graphene channel. Furthermore, the outstanding properties of graphene, with long-distance spin transport and higher electrical resistivity than metals, allow us to achieve in our graphene/Pt lateral heterostructures the largest spin-to-charge output voltage at room temperature reported so far in the literature. Our approach opens up exciting opportunities towards the implementation of spin-orbit-based logic circuits and all electrical control of spin information without magnetic field. Spintronic devices with full electrical control rely on electrical generation and detection of spin currents in the absence of magnetic materials. Here, the authors use Pt, a non-magnetic metal, to generate and detect pure spin currents in a few-layer graphene channel, achieving a remarkable spin-to-charge voltage signal at room temperature.
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47
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Enhanced paramagnetism of mesoscopic graphdiyne by doping with nitrogen. Sci Rep 2017; 7:11535. [PMID: 28912523 PMCID: PMC5599548 DOI: 10.1038/s41598-017-11698-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 08/29/2017] [Indexed: 11/08/2022] Open
Abstract
The new two-dimensional graphitic material, graphdiyne, has attracted great interest recently due to the superior intrinsic semiconductor properties. Here we investigate the magnetism of pure graphdiyne material and find it demonstrating a remarkable paramagnetic characteristic, which can be attributed to the appearance of special sp-hybridized carbon atoms. On this basis, we further introduce nitrogen with 5.29% N/C ratio into graphdiyne followed by simply annealing in a dopant source and realize a twofold enhancement of saturation moment at 2 K. Associate with the density of states calculation, we investigate the influence of the nitrogen atom doping sites on paramagnetism, and further reveal the important role of doped nitrogen atom on benzene ring in improving local magnetic moment. These results can not only help us deeply understand the intrinsic magnetism of graphdiyne, but also open an efficient way to improve magnetism of graphdiyne by hetero atom doping, like nitrogen doping, which may promote the potential application of graphdiyne in spintronics.
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48
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Garcia JH, Cummings AW, Roche S. Spin Hall Effect and Weak Antilocalization in Graphene/Transition Metal Dichalcogenide Heterostructures. NANO LETTERS 2017; 17:5078-5083. [PMID: 28715194 DOI: 10.1021/acs.nanolett.7b02364] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We report on a theoretical study of the spin Hall Effect (SHE) and weak antilocalization (WAL) in graphene/transition metal dichalcogenide (TMDC) heterostructures, computed through efficient real-space quantum transport methods, and using realistic tight-binding models parametrized from ab initio calculations. The graphene/WS2 system is found to maximize spin proximity effects compared to graphene on MoS2, WSe2, or MoSe2 with a crucial role played by disorder, given the disappearance of SHE signals in the presence of strong intervalley scattering. Notably, we found that stronger WAL effects are concomitant with weaker charge-to-spin conversion efficiency. For further experimental studies of graphene/TMDC heterostructures, our findings provide guidelines for reaching the upper limit of spin current formation and for fully harvesting the potential of two-dimensional materials for spintronic applications.
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Affiliation(s)
- Jose H Garcia
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology , Campus UAB, 08193 Barcelona, Spain
| | - Aron W Cummings
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology , Campus UAB, 08193 Barcelona, Spain
| | - Stephan Roche
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology , Campus UAB, 08193 Barcelona, Spain
- ICREA - Institució Catalana de Recerca i Estudis Avançats , 08010 Barcelona, Spain
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49
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Ukpong AM. Ab initio studies of coherent spin transport in Fe-hBN/graphene van der Waals multilayers. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:285302. [PMID: 28531091 DOI: 10.1088/1361-648x/aa74a4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
This paper presents the results of ab initio studies of the electronic spin inversion and filtering in a ferromagnetic multilayer heterostructure. Spin-polarized electronic structure calculations are performed based on van der Waals density functional theory to give unique insights in to the generation, manipulation and transport of coherent spin conductance. By using an exact theory of the self-consistent ground state of the Fe-hBN/graphene multilayer as a model of the magnetic tunnel junction, hidden asymmetries are unraveled in the spin-resolved charge densities. It is shown that the injection of spin into the graphene/boron nitride tunnel layer from a ferromagnetic contact gives rise to coherent spin current. The projected Fermi surfaces of the up and down spin channels are analyzed to reveal Fermi arc topologies and spin anisotropies. It is also demonstrated that the coherent transport of pure spin-down current in the topological Weyl semimetal phase is robust. The implications of the results on out-of-plane transport of spin polarized conductance in van der Waals multilayer spintronic devices is discussed. The insights derived from this study are expected to open up prospects for further exploration of van der Waals magnetic multilayer heterostructures as a versatile platform for developing materials for Weyltronic applications.
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Affiliation(s)
- Aniekan Magnus Ukpong
- Theoretical and Computational Condensed Matter and Materials Physics Group, School of Chemistry and Physics, College of Agriculture, Engineering and Science, University of KwaZulu-Natal, 1 King Edward Road, Scottsville 3201, Pietermaritzburg, South Africa
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50
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Electrical gate control of spin current in van der Waals heterostructures at room temperature. Nat Commun 2017; 8:16093. [PMID: 28677673 PMCID: PMC5504284 DOI: 10.1038/ncomms16093] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 05/25/2017] [Indexed: 12/23/2022] Open
Abstract
Two-dimensional (2D) crystals offer a unique platform due to their remarkable and contrasting spintronic properties, such as weak spin–orbit coupling (SOC) in graphene and strong SOC in molybdenum disulfide (MoS2). Here we combine graphene and MoS2 in a van der Waals heterostructure (vdWh) to demonstrate the electric gate control of the spin current and spin lifetime at room temperature. By performing non-local spin valve and Hanle measurements, we unambiguously prove the gate tunability of the spin current and spin lifetime in graphene/MoS2 vdWhs at 300 K. This unprecedented control over the spin parameters by orders of magnitude stems from the gate tuning of the Schottky barrier at the MoS2/graphene interface and MoS2 channel conductivity leading to spin dephasing in high-SOC material. Our findings demonstrate an all-electrical spintronic device at room temperature with the creation, transport and control of the spin in 2D materials heterostructures, which can be key building blocks in future device architectures. Two-dimensional materials are unique to build heterostructures with contrasting spintronic properties. Here, Dankert and Dash utilize a van der Waals heterostructure with graphene and MoS2 to demonstrate an all-electrical device for creation, transport and control of the spin current up to room temperature.
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