1
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Wu W, Liu M, Zhou J, Li J, Zhang Y, Xu F, Li X, Wu Y, Wu Z, Kang J. Chirality-Dependent Valley Polarization in Magnetic van der Waals Heterostructures via Spin-Selective Charge Transfer. NANO LETTERS 2024; 24:6225-6232. [PMID: 38752702 DOI: 10.1021/acs.nanolett.4c00503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2024]
Abstract
Magnetic proximity interaction provides a promising route to manipulate the spin and valley degrees of freedom in van der Waals heterostructures. Here, we report a control of valley pseudospin in the WS2/MoSe2 heterostructure by utilizing the magnetic proximity effect of few-layered CrBr3 and, for the first time, observe a substantial difference in valley polarization of intra/interlayer excitons under different circularly polarized laser excitations, referred to as chirality-dependent valley polarization. Theoretical and experimental results reveal that the spin-selective charge transfer between MoSe2 and CrBr3, as well as between MoSe2 and WS2, is mostly responsible for the chiral feature of valley polarization in comparison with the proximity exchange field. This means that a long-distance manipulation of exciton behaviors in multilayer heterostructures can be achieved through spin-selective charge transfer. This work marks a significant advancement in the control of spin and valley pseudospin in multilayer structures.
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Affiliation(s)
- Wei Wu
- Department of Physics, Engineering Research Center for Micro-Nano Optoelectronic Materials and Devices of Ministry of Education, OSED, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Xiamen University, Xiamen 361005, People's Republic of China
| | - Mengyu Liu
- Department of Physics, Engineering Research Center for Micro-Nano Optoelectronic Materials and Devices of Ministry of Education, OSED, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Xiamen University, Xiamen 361005, People's Republic of China
| | - Jiangpeng Zhou
- Department of Physics, Engineering Research Center for Micro-Nano Optoelectronic Materials and Devices of Ministry of Education, OSED, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Xiamen University, Xiamen 361005, People's Republic of China
| | - Jin'an Li
- Department of Physics, Engineering Research Center for Micro-Nano Optoelectronic Materials and Devices of Ministry of Education, OSED, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Xiamen University, Xiamen 361005, People's Republic of China
| | - Yuxiang Zhang
- Department of Physics, Engineering Research Center for Micro-Nano Optoelectronic Materials and Devices of Ministry of Education, OSED, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Xiamen University, Xiamen 361005, People's Republic of China
| | - Feiya Xu
- Department of Physics, Engineering Research Center for Micro-Nano Optoelectronic Materials and Devices of Ministry of Education, OSED, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Xiamen University, Xiamen 361005, People's Republic of China
| | - Xu Li
- Department of Physics, Engineering Research Center for Micro-Nano Optoelectronic Materials and Devices of Ministry of Education, OSED, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Xiamen University, Xiamen 361005, People's Republic of China
| | - Yaping Wu
- Department of Physics, Engineering Research Center for Micro-Nano Optoelectronic Materials and Devices of Ministry of Education, OSED, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Xiamen University, Xiamen 361005, People's Republic of China
| | - Zhiming Wu
- Department of Physics, Engineering Research Center for Micro-Nano Optoelectronic Materials and Devices of Ministry of Education, OSED, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Xiamen University, Xiamen 361005, People's Republic of China
| | - Junyong Kang
- Department of Physics, Engineering Research Center for Micro-Nano Optoelectronic Materials and Devices of Ministry of Education, OSED, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Xiamen University, Xiamen 361005, People's Republic of China
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2
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Liu H, Wu Y, Wu Z, Liu S, Zhang VL, Yu T. Coexisting Phases in Transition Metal Dichalcogenides: Overview, Synthesis, Applications, and Prospects. ACS NANO 2024; 18:2708-2729. [PMID: 38252696 DOI: 10.1021/acsnano.3c10665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Over the past decade, significant advancements have been made in phase engineering of two-dimensional transition metal dichalcogenides (TMDCs), thereby allowing controlled synthesis of various phases of TMDCs and facile conversion between them. Recently, there has been emerging interest in TMDC coexisting phases, which contain multiple phases within one nanostructured TMDC. By taking advantage of the merits from the component phases, the coexisting phases offer enhanced performance in many aspects compared with single-phase TMDCs. Herein, this review article thoroughly expounds the latest progress and ongoing efforts on the syntheses, properties, and applications of TMDC coexisting phases. The introduction section overviews the main phases of TMDCs (2H, 3R, 1T, 1T', 1Td), along with the advantages of phase coexistence. The subsequent section focuses on the synthesis methods for coexisting phases of TMDCs, with particular attention to local patterning and random formations. Furthermore, on the basis of the versatile properties of TMDC coexisting phases, their applications in magnetism, valleytronics, field-effect transistors, memristors, and catalysis are discussed. Lastly, a perspective is presented on the future development, challenges, and potential opportunities of TMDC coexisting phases. This review aims to provide insights into the phase engineering of 2D materials for both scientific and engineering communities and contribute to further advancements in this emerging field.
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Affiliation(s)
- Haiyang Liu
- School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - Yaping Wu
- School of Physics and Technology, Xiamen University, Xiamen 361005, China
| | - Zhiming Wu
- School of Physics and Technology, Xiamen University, Xiamen 361005, China
| | - Sheng Liu
- School of Physics and Technology, Wuhan University, Wuhan 430072, China
- Wuhan Institute of Quantum Technology, Wuhan 430206, China
| | - Vanessa Li Zhang
- School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - Ting Yu
- School of Physics and Technology, Wuhan University, Wuhan 430072, China
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3
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Serati de Brito C, Faria Junior PE, Ghiasi TS, Ingla-Aynés J, Rabahi CR, Cavalini C, Dirnberger F, Mañas-Valero S, Watanabe K, Taniguchi T, Zollner K, Fabian J, Schüller C, van der Zant HSJ, Gobato YG. Charge Transfer and Asymmetric Coupling of MoSe 2 Valleys to the Magnetic Order of CrSBr. NANO LETTERS 2023. [PMID: 38019289 DOI: 10.1021/acs.nanolett.3c03431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2023]
Abstract
van der Waals heterostructures composed of two-dimensional (2D) transition metal dichalcogenides and vdW magnetic materials offer an intriguing platform to functionalize valley and excitonic properties in nonmagnetic TMDs. Here, we report magneto photoluminescence (PL) investigations of monolayer (ML) MoSe2 on the layered A-type antiferromagnetic (AFM) semiconductor CrSBr under different magnetic field orientations. Our results reveal a clear influence of the CrSBr magnetic order on the optical properties of MoSe2, such as an anomalous linear-polarization dependence, changes of the exciton/trion energies, a magnetic-field dependence of the PL intensities, and a valley g-factor with signatures of an asymmetric magnetic proximity interaction. Furthermore, first-principles calculations suggest that MoSe2/CrSBr forms a broken-gap (type-III) band alignment, facilitating charge transfer processes. The work establishes that antiferromagnetic-nonmagnetic interfaces can be used to control the valley and excitonic properties of TMDs, relevant for the development of opto-spintronics devices.
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Affiliation(s)
- Caique Serati de Brito
- Physics Department, Federal University of São Carlos, São Carlos, SP 13565-905, Brazil
- Institut für Experimentelle und Angewandte Physik, Universität Regensburg, D-93040 Regensburg, Germany
| | - Paulo E Faria Junior
- Institute for Theoretical Physics, University of Regensburg, D-93040 Regensburg, Germany
| | - Talieh S Ghiasi
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - Josep Ingla-Aynés
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - César Ricardo Rabahi
- Physics Department, Federal University of São Carlos, São Carlos, SP 13565-905, Brazil
| | - Camila Cavalini
- Physics Department, Federal University of São Carlos, São Carlos, SP 13565-905, Brazil
| | - Florian Dirnberger
- Institute of Applied Physics and Würzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität, 01069 Dresden, Germany
| | - Samuel Mañas-Valero
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
- Instituto de Ciencia Molecular (ICMol), Universitat de València, Catedrático José Beltrán 2, Paterna 46980, Spain
| | - Kenji Watanabe
- Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Klaus Zollner
- Institute for Theoretical Physics, University of Regensburg, D-93040 Regensburg, Germany
| | - Jaroslav Fabian
- Institute for Theoretical Physics, University of Regensburg, D-93040 Regensburg, Germany
| | - Christian Schüller
- Institut für Experimentelle und Angewandte Physik, Universität Regensburg, D-93040 Regensburg, Germany
| | - Herre S J van der Zant
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - Yara Galvão Gobato
- Physics Department, Federal University of São Carlos, São Carlos, SP 13565-905, Brazil
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4
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Gao Z, He Y, Xiong K. Two-dimensional Janus SVAN 2 (A = Si, Ge) monolayers with intrinsic semiconductor character and room temperature ferromagnetism: tunable electronic properties via strain and an electric field. Dalton Trans 2023; 52:17416-17425. [PMID: 37947052 DOI: 10.1039/d3dt03031h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
In the context of developing next-generation information technology, two-dimensional materials with inherent ferromagnetism, a Curie temperature above room temperature, and significant magnetic anisotropy hold great promise. In this work, we employed first-principles calculations to investigate a novel two-dimensional Janus structure, namely SVAN2 (A = Si, Ge). Our findings reveal that these structures are not only dynamically and thermally stable, but also exhibit semiconductor properties alongside their ferromagnetic states. The Janus SVSiN2 monolayer exhibits an in-plane easy axis, while the SVGeN2 monolayer shows an out-of-plane easy axis, both characterized by a significant magnetic anisotropy energy (129 and 172 μeV, respectively). Notably, through Monte Carlo simulation, we found that the Curie temperature of the SVSiN2 monolayer is 330 K, which is higher than room temperature. Finally, by applying biaxial strain and an external electric field, we successfully regulated the electronic properties of the SVAN2 (A = Si, Ge) monolayers, enabling a transition from semiconductor to half-metallic behavior. These remarkable electronic and magnetic properties make the Janus SVAN2 (A = Si, Ge) monolayers promising candidate materials for spin electron applications.
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Affiliation(s)
- Zhen Gao
- Department of Physics, Yunnan University, Kunming 650091, People's Republic of China.
| | - Yao He
- Department of Physics, Yunnan University, Kunming 650091, People's Republic of China.
| | - Kai Xiong
- Materials Genome Institute, School of Materials and Energy, Yunnan University, Kunming 650091, P. R. China
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5
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Li X, Jones AC, Choi J, Zhao H, Chandrasekaran V, Pettes MT, Piryatinski A, Tschudin MA, Reiser P, Broadway DA, Maletinsky P, Sinitsyn N, Crooker SA, Htoon H. Proximity-induced chiral quantum light generation in strain-engineered WSe 2/NiPS 3 heterostructures. NATURE MATERIALS 2023; 22:1311-1316. [PMID: 37592028 DOI: 10.1038/s41563-023-01645-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 07/18/2023] [Indexed: 08/19/2023]
Abstract
Quantum light emitters capable of generating single photons with circular polarization and non-classical statistics could enable non-reciprocal single-photon devices and deterministic spin-photon interfaces for quantum networks. To date, the emission of such chiral quantum light relies on the application of intense external magnetic fields, electrical/optical injection of spin-polarized carriers/excitons or coupling with complex photonic metastructures. Here we report the creation of free-space chiral quantum light emitters via the nanoindentation of monolayer WSe2/NiPS3 heterostructures at zero external magnetic field. These quantum light emitters emit with a high degree of circular polarization (0.89) and single-photon purity (95%), independent of pump laser polarization. Scanning diamond nitrogen-vacancy microscopy and temperature-dependent magneto-photoluminescence studies reveal that the chiral quantum light emission arises from magnetic proximity interactions between localized excitons in the WSe2 monolayer and the out-of-plane magnetization of defects in the antiferromagnetic order of NiPS3, both of which are co-localized by strain fields associated with the nanoscale indentations.
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Affiliation(s)
- Xiangzhi Li
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Andrew C Jones
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Junho Choi
- National High Magnetic Field Laboratory, Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Huan Zhao
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Vigneshwaran Chandrasekaran
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Michael T Pettes
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Andrei Piryatinski
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | | | - Patrick Reiser
- Department of Physics, University of Basel, Basel, Switzerland
| | | | | | - Nikolai Sinitsyn
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Scott A Crooker
- National High Magnetic Field Laboratory, Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Han Htoon
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM, USA.
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6
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Pawbake A, Pelini T, Mohelsky I, Jana D, Breslavetz I, Cho CW, Orlita M, Potemski M, Measson MA, Wilson NP, Mosina K, Soll A, Sofer Z, Piot BA, Zhitomirsky ME, Faugeras C. Magneto-Optical Sensing of the Pressure Driven Magnetic Ground States in Bulk CrSBr. NANO LETTERS 2023; 23:9587-9593. [PMID: 37823538 DOI: 10.1021/acs.nanolett.3c03216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/13/2023]
Abstract
Competition between exchange interactions and magnetocrystalline anisotropy may bring new magnetic states that are of great current interest. An applied hydrostatic pressure can further be used to tune their balance. In this work, we investigate the magnetization process of a biaxial antiferromagnet in an external magnetic field applied along the easy axis. We find that the single metamagnetic transition of the Ising type observed in this material under ambient pressure transforms under hydrostatic pressure into two transitions, a first-order spin-flop transition followed by a second-order transition toward a polarized ferromagnetic state near saturation. This reversible tuning into a new magnetic phase is obtained in layered bulk CrSBr at low temperature by varying the interlayer distance using high hydrostatic pressure, which efficiently acts on the interlayer magnetic exchange and is probed by magneto-optical spectroscopy.
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Affiliation(s)
- Amit Pawbake
- LNCMI, UPR 3228, CNRS, EMFL, Université Grenoble Alpes, 38000 Grenoble, France
| | - Thomas Pelini
- LNCMI, UPR 3228, CNRS, EMFL, Université Grenoble Alpes, 38000 Grenoble, France
| | - Ivan Mohelsky
- LNCMI, UPR 3228, CNRS, EMFL, Université Grenoble Alpes, 38000 Grenoble, France
| | - Dipankar Jana
- LNCMI, UPR 3228, CNRS, EMFL, Université Grenoble Alpes, 38000 Grenoble, France
| | - Ivan Breslavetz
- LNCMI, UPR 3228, CNRS, EMFL, Université Grenoble Alpes, 38000 Grenoble, France
| | - Chang-Woo Cho
- LNCMI, UPR 3228, CNRS, EMFL, Université Grenoble Alpes, 38000 Grenoble, France
| | - Milan Orlita
- LNCMI, UPR 3228, CNRS, EMFL, Université Grenoble Alpes, 38000 Grenoble, France
| | - Marek Potemski
- LNCMI, UPR 3228, CNRS, EMFL, Université Grenoble Alpes, 38000 Grenoble, France
- CENTERA Laboratories, Institute of High Pressure Physics, PAS, 01-142 Warsaw, Poland
| | | | - Nathan P Wilson
- Walter Schottky Institut, Physics Department and MCQST, Technische Universitat Munchen, 85748 Garching, Germany
| | - Kseniia Mosina
- Department of Inorganic Chemistry, University of Chemistry and Technology Prague, Technicka 5, 166 28 Prague 6, Czech Republic
| | - Aljoscha Soll
- Department of Inorganic Chemistry, University of Chemistry and Technology Prague, Technicka 5, 166 28 Prague 6, Czech Republic
| | - Zdenek Sofer
- Department of Inorganic Chemistry, University of Chemistry and Technology Prague, Technicka 5, 166 28 Prague 6, Czech Republic
| | - Benjamin A Piot
- LNCMI, UPR 3228, CNRS, EMFL, Université Grenoble Alpes, 38000 Grenoble, France
| | - Mike E Zhitomirsky
- Université Grenoble Alpes, CEA, Grenoble INP, IRIG, Pheliqs, 38000 Grenoble, France
- Institut Laue-Langevin, F-38042 Grenoble Cedex 9, France
| | - Clement Faugeras
- LNCMI, UPR 3228, CNRS, EMFL, Université Grenoble Alpes, 38000 Grenoble, France
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7
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Jiao C, Pei S, Wu S, Wang Z, Xia J. Tuning and exploiting interlayer coupling in two-dimensional van der Waals heterostructures. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2023; 86:114503. [PMID: 37774692 DOI: 10.1088/1361-6633/acfe89] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Accepted: 09/29/2023] [Indexed: 10/01/2023]
Abstract
Two-dimensional (2D) layered materials can stack into new material systems, with van der Waals (vdW) interaction between the adjacent constituent layers. This stacking process of 2D atomic layers creates a new degree of freedom-interlayer interface between two adjacent layers-that can be independently studied and tuned from the intralayer degree of freedom. In such heterostructures (HSs), the physical properties are largely determined by the vdW interaction between the individual layers,i.e.interlayer coupling, which can be effectively tuned by a number of means. In this review, we summarize and discuss a number of such approaches, including stacking order, electric field, intercalation, and pressure, with both their experimental demonstrations and theoretical predictions. A comprehensive overview of the modulation on structural, optical, electrical, and magnetic properties by these four approaches are also presented. We conclude this review by discussing several prospective research directions in 2D HSs field, including fundamental physics study, property tuning techniques, and future applications.
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Affiliation(s)
- Chenyin Jiao
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 610054, People's Republic of China
| | - Shenghai Pei
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 610054, People's Republic of China
| | - Song Wu
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 610054, People's Republic of China
| | - Zenghui Wang
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 610054, People's Republic of China
| | - Juan Xia
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 610054, People's Republic of China
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8
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Ren H, Xiang G. Strain Engineering of Intrinsic Ferromagnetism in 2D van der Waals Materials. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2378. [PMID: 37630963 PMCID: PMC10459406 DOI: 10.3390/nano13162378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Revised: 08/09/2023] [Accepted: 08/17/2023] [Indexed: 08/27/2023]
Abstract
Since the discovery of the low-temperature, long-range ferromagnetic order in monolayers Cr2Ge2Te6 and CrI3, many efforts have been made to achieve a room temperature (RT) ferromagnet. The outstanding deformation ability of two-dimensional (2D) materials provides an exciting way to mediate their intrinsic ferromagnetism (FM) with strain engineering. Here, we summarize the recent progress of strain engineering of intrinsic FM in 2D van der Waals materials. First, we introduce how to explain the strain-mediated intrinsic FM on Cr-based and Fe-based 2D van der Waals materials through ab initio Density functional theory (DFT), and how to calculate magnetic anisotropy energy (MAE) and Curie temperature (TC) from the interlayer exchange coupling J. Subsequently, we focus on numerous attempts to apply strain to 2D materials in experiments, including wrinkle-induced strain, flexible substrate bending or stretching, lattice mismatch, electrostatic force and field-cooling. Last, we emphasize that this field is still in early stages, and there are many challenges that need to be overcome. More importantly, strengthening the guideline of strain-mediated FM in 2D van der Waals materials will promote the development of spintronics and straintronics.
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Affiliation(s)
- Hongtao Ren
- School of Materials Science and Engineering, Liaocheng University, Hunan Road No. 1, Liaocheng 252000, China
| | - Gang Xiang
- College of Physics, Sichuan University, Wangjiang Road No. 29, Chengdu 610064, China
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9
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Xu H, Jia K, Huang Y, Meng F, Zhang Q, Zhang Y, Cheng C, Lan G, Dong J, Wei J, Feng J, He C, Yuan Z, Zhu M, He W, Wan C, Wei H, Wang S, Shao Q, Gu L, Coey M, Shi Y, Zhang G, Han X, Yu G. Electrical detection of spin pumping in van der Waals ferromagnetic Cr 2Ge 2Te 6 with low magnetic damping. Nat Commun 2023; 14:3824. [PMID: 37380642 DOI: 10.1038/s41467-023-39529-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 06/15/2023] [Indexed: 06/30/2023] Open
Abstract
The discovery of magnetic order in atomically-thin van der Waals materials has strengthened the alliance between spintronics and two-dimensional materials. An important use of magnetic two-dimensional materials in spintronic devices, which has not yet been demonstrated, would be for coherent spin injection via the spin-pumping effect. Here, we report spin pumping from Cr2Ge2Te6 into Pt or W and detection of the spin current by inverse spin Hall effect. The magnetization dynamics of the hybrid Cr2Ge2Te6/Pt system are measured, and a magnetic damping constant of ~ 4-10 × 10-4 is obtained for thick Cr2Ge2Te6 flakes, a record low for ferromagnetic van der Waals materials. Moreover, a high interface spin transmission efficiency (a spin mixing conductance of 2.4 × 1019/m2) is directly extracted, which is instrumental in delivering spin-related quantities such as spin angular momentum and spin-orbit torque across an interface of the van der Waals system. The low magnetic damping that promotes efficient spin current generation together with high interfacial spin transmission efficiency suggests promising applications for integrating Cr2Ge2Te6 into low-temperature two-dimensional spintronic devices as the source of coherent spin or magnon current.
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Affiliation(s)
- Hongjun Xu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
| | - Ke Jia
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yuan Huang
- Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing, 100081, China
| | - Fanqi Meng
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
| | - Qinghua Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, China
| | - Yu Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Chen Cheng
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Guibin Lan
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jing Dong
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jinwu Wei
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, China
- Key Laboratory of Magnetism and Magnetic Materials of the Ministry of Education, School of Physical Science and Technology, Lanzhou University, Lanzhou, 730000, China
| | - Jiafeng Feng
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Congli He
- Institute of Advanced Materials, Beijing Normal University, Beijing, 100875, China
| | - Zhe Yuan
- Department of Physics, Beijing Normal University, Beijing, 100875, China
| | - Mingliang Zhu
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China
| | - Wenqing He
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Caihua Wan
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Hongxiang Wei
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, China
| | - Shouguo Wang
- School of Materials Science and Engineering, Anhui University, Hefei, 230601, China
| | - Qiming Shao
- Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology, Kowloon, Hong Kong, China
| | - Lin Gu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Michael Coey
- School of Physics and CRANN, Trinity College, Dublin, 2, Ireland
| | - Youguo Shi
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Guangyu Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiufeng Han
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Guoqiang Yu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, China.
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China.
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China.
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10
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Rong R, Liu Y, Nie X, Zhang W, Zhang Z, Liu Y, Guo W. The Interaction of 2D Materials With Circularly Polarized Light. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2206191. [PMID: 36698292 PMCID: PMC10074140 DOI: 10.1002/advs.202206191] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 12/16/2022] [Indexed: 06/17/2023]
Abstract
2D materials (2DMs), due to spin-valley locking degree of freedom, exhibit strongly bound exciton and chiral optical selection rules and become promising material candidates for optoelectronic and spin/valleytronic devices. Over the last decade, the manifesting of 2D materials by circularly polarized lights expedites tremendous fascinating phenomena, such as valley/exciton Hall effect, Moiré exciton, optical Stark effect, circular dichroism, circularly polarized photoluminescence, and spintronic property. In this review, recent advance in the interaction of circularly polarized light with 2D materials covering from graphene, black phosphorous, transition metal dichalcogenides, van der Waals heterostructures as well as small proportion of quasi-2D perovskites and topological materials, is overviewed. The confronted challenges and theoretical and experimental opportunities are also discussed, attempting to accelerate the prosperity of chiral light-2DMs interactions.
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Affiliation(s)
- Rong Rong
- Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of EducationState Key Laboratory of Mechanics and Control of Mechanical Structuresand Institute for Frontier ScienceNanjing University of Aeronautics and AstronauticsNanjing210016China
| | - Ying Liu
- Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of EducationState Key Laboratory of Mechanics and Control of Mechanical Structuresand Institute for Frontier ScienceNanjing University of Aeronautics and AstronauticsNanjing210016China
| | - Xuchen Nie
- Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of EducationState Key Laboratory of Mechanics and Control of Mechanical Structuresand Institute for Frontier ScienceNanjing University of Aeronautics and AstronauticsNanjing210016China
| | - Wei Zhang
- Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of EducationState Key Laboratory of Mechanics and Control of Mechanical Structuresand Institute for Frontier ScienceNanjing University of Aeronautics and AstronauticsNanjing210016China
| | - Zhuhua Zhang
- Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of EducationState Key Laboratory of Mechanics and Control of Mechanical Structuresand Institute for Frontier ScienceNanjing University of Aeronautics and AstronauticsNanjing210016China
| | - Yanpeng Liu
- Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of EducationState Key Laboratory of Mechanics and Control of Mechanical Structuresand Institute for Frontier ScienceNanjing University of Aeronautics and AstronauticsNanjing210016China
| | - Wanlin Guo
- Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of EducationState Key Laboratory of Mechanics and Control of Mechanical Structuresand Institute for Frontier ScienceNanjing University of Aeronautics and AstronauticsNanjing210016China
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11
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Faria Junior PE, Fabian J. Signatures of Electric Field and Layer Separation Effects on the Spin-Valley Physics of MoSe 2/WSe 2 Heterobilayers: From Energy Bands to Dipolar Excitons. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:1187. [PMID: 37049281 PMCID: PMC10096971 DOI: 10.3390/nano13071187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/22/2023] [Accepted: 03/24/2023] [Indexed: 06/19/2023]
Abstract
Multilayered van der Waals heterostructures based on transition metal dichalcogenides are suitable platforms on which to study interlayer (dipolar) excitons, in which electrons and holes are localized in different layers. Interestingly, these excitonic complexes exhibit pronounced valley Zeeman signatures, but how their spin-valley physics can be further altered due to external parameters-such as electric field and interlayer separation-remains largely unexplored. Here, we perform a systematic analysis of the spin-valley physics in MoSe2/WSe2 heterobilayers under the influence of an external electric field and changes of the interlayer separation. In particular, we analyze the spin (Sz) and orbital (Lz) degrees of freedom, and the symmetry properties of the relevant band edges (at K, Q, and Γ points) of high-symmetry stackings at 0° (R-type) and 60° (H-type) angles-the important building blocks present in moiré or atomically reconstructed structures. We reveal distinct hybridization signatures on the spin and the orbital degrees of freedom of low-energy bands, due to the wave function mixing between the layers, which are stacking-dependent, and can be further modified by electric field and interlayer distance variation. We find that H-type stackings favor large changes in the g-factors as a function of the electric field, e.g., from -5 to 3 in the valence bands of the Hhh stacking, because of the opposite orientation of Sz and Lz of the individual monolayers. For the low-energy dipolar excitons (direct and indirect in k-space), we quantify the electric dipole moments and polarizabilities, reflecting the layer delocalization of the constituent bands. Furthermore, our results show that direct dipolar excitons carry a robust valley Zeeman effect nearly independent of the electric field, but tunable by the interlayer distance, which can be rendered experimentally accessible via applied external pressure. For the momentum-indirect dipolar excitons, our symmetry analysis indicates that phonon-mediated optical processes can easily take place. In particular, for the indirect excitons with conduction bands at the Q point for H-type stackings, we find marked variations of the valley Zeeman (∼4) as a function of the electric field, which notably stands out from the other dipolar exciton species. Our analysis suggests that stronger signatures of the coupled spin-valley physics are favored in H-type stackings, which can be experimentally investigated in samples with twist angle close to 60°. In summary, our study provides fundamental microscopic insights into the spin-valley physics of van der Waals heterostructures, which are relevant to understanding the valley Zeeman splitting of dipolar excitonic complexes, and also intralayer excitons.
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12
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Choi J, Lane C, Zhu JX, Crooker SA. Asymmetric magnetic proximity interactions in MoSe 2/CrBr 3 van der Waals heterostructures. NATURE MATERIALS 2023; 22:305-310. [PMID: 36536140 DOI: 10.1038/s41563-022-01424-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 10/27/2022] [Indexed: 06/17/2023]
Abstract
Magnetic proximity interactions between atomically thin semiconductors and two-dimensional magnets provide a means to manipulate spin and valley degrees of freedom in non-magnetic monolayers, without using applied magnetic fields1-3. In such van der Waals heterostructures, magnetic proximity interactions originate in the nanometre-scale coupling between spin-dependent electronic wavefunctions in the two materials, and typically their overall effect is regarded as an effective magnetic field acting on the semiconductor monolayer4-8. Here we demonstrate that magnetic proximity interactions in van der Waals heterostructures can in fact be markedly asymmetric. Valley-resolved reflection spectroscopy of MoSe2/CrBr3 van der Waals structures reveals strikingly different energy shifts in the K and K' valleys of the MoSe2 due to ferromagnetism in the CrBr3 layer. Density functional calculations indicate that valley-asymmetric magnetic proximity interactions depend sensitively on the spin-dependent hybridization of overlapping bands and as such are likely a general feature of hybrid van der Waals structures. These studies suggest routes to control specific spin and valley states in monolayer semiconductors9,10.
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Affiliation(s)
- Junho Choi
- National High Magnetic Field Laboratory, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Christopher Lane
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM, USA
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Jian-Xin Zhu
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM, USA
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Scott A Crooker
- National High Magnetic Field Laboratory, Los Alamos National Laboratory, Los Alamos, NM, USA.
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13
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Fumega AO, Lado JL. Ferroelectric valley valves with graphene/MoTe 2 van der Waals heterostructures. NANOSCALE 2023; 15:2181-2187. [PMID: 36633129 DOI: 10.1039/d2nr05185k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Ferroelectric van der Waals heterostructures provide a natural platform to design a variety of electrically controllable devices. In this work, we demonstrate that AB bilayer graphene encapsulated in MoTe2 acts as a valley valve that displays a switchable built-in topological gap, leading to ferroelectrically driven topological channels. Using a combination of ab initio calculations and low energy models, we show that the ferroelectric order of MoTe2 allows the control of the gap opening in bilayer graphene and leads to topological channels between different ferroelectric domains. Moreover, we analyze the effect that the moiré modulation between MoTe2 and graphene layers has in the topological modes, demonstrating that the edge states are robust against moiré modulations of the ferroelectrically-induced electric potential. Our results put forward ferroelectric/graphene heterostructures as versatile platforms to engineer switchable built-in topological channels without requiring an external electric bias.
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Affiliation(s)
- Adolfo O Fumega
- Department of Applied Physics, Aalto University, 02150 Espoo, Finland
| | - Jose L Lado
- Department of Applied Physics, Aalto University, 02150 Espoo, Finland
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14
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Zhang D, Zhang Y, Zhou B. Nonvolatile electrical control of valley splitting by ferroelectric polarization switching in a two-dimensional AgBiP 2S 6/CrBr 3 multiferroic heterostructure. NANOSCALE 2023; 15:1718-1729. [PMID: 36594597 DOI: 10.1039/d2nr04956b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The generation and controllability of valley splitting are the major challenge in effectively utilizing valley degrees of freedom in valleytronics. Using first-principles calculations, we propose a novel multiferroic system, a AgBiP2S6/CrBr3 van der Waals heterostructure, with ferromagnetism, ferroelectricity and ferrovalley behaviors. The ferroelectric monolayer AgBiP2S6 originally has two degenerate valleys with a large spin splitting (∼423.1 meV) at the conduction band minimum of K/K' points, due to inversion symmetry breaking combined with strong spin orbit coupling. Magnetic proximity coupling with the ferromagnetic layer CrBr3 breaks the time-reversal symmetry, damaging the degeneracy of K/K' valleys and causing valley splitting (∼30.5 meV). The transition energy barrier between two ferroelectric states with opposite polarization direction of the heterostructure is sufficient to prevent the spontaneous transition at room temperature, and the large intermediate barrier suggests that the ferroelectric state should be observed experimentally under ambient conditions. Nonvolatile electrical control of the valley degrees of freedom is achieved by switching the polarization direction of the ferroelectric layer in the heterostructure. The modulation of valley splitting can also be achieved by applying an external electric field and biaxial strain, as well as changing the magnetization direction. The research of nonvolatile electrical control of valley splitting in the two-dimensional AgBiP2S6/CrBr3 multiferroic heterostructure is crucial for designing all-in-one valleytronic devices, and has important theoretical significance and practical value.
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Affiliation(s)
- Dongxue Zhang
- Tianjin Key Laboratory of Film Electronic & Communicate Devices, School of Integrated Circuit Science and Engineering, Tianjin University of Technology, Tianjin 300384, China.
| | - Yifan Zhang
- Tianjin Key Laboratory of Film Electronic & Communicate Devices, School of Integrated Circuit Science and Engineering, Tianjin University of Technology, Tianjin 300384, China.
| | - Baozeng Zhou
- Tianjin Key Laboratory of Film Electronic & Communicate Devices, School of Integrated Circuit Science and Engineering, Tianjin University of Technology, Tianjin 300384, China.
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15
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Vadia S, Scherzer J, Watanabe K, Taniguchi T, Högele A. Magneto-Optical Chirality in a Coherently Coupled Exciton-Plasmon System. NANO LETTERS 2023; 23:614-618. [PMID: 36617344 PMCID: PMC9881169 DOI: 10.1021/acs.nanolett.2c04246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 12/22/2022] [Indexed: 06/17/2023]
Abstract
Chirality is a fundamental asymmetry phenomenon, with chiral optical elements exhibiting asymmetric response in reflection or absorption of circularly polarized light. Recent realizations of such elements include nanoplasmonic systems with broken-mirror symmetry and polarization-contrasting optical absorption known as circular dichroism. An alternative route to circular dichroism is provided by spin-valley polarized excitons in atomically thin semiconductors. In the presence of magnetic fields, they exhibit an imbalanced coupling to circularly polarized photons and thus circular dichroism. Here, we demonstrate that polarization-contrasting optical transitions associated with excitons in monolayer WSe2 can be transferred to proximal plasmonic nanodisks by coherent coupling. The coupled exciton-plasmon system exhibits magneto-induced circular dichroism in a spectrally narrow window of Fano interference, which we model in a master equation framework. Our work motivates the use of exciton-plasmon interfaces as building blocks of chiral metasurfaces for applications in information processing, nonlinear optics, and sensing.
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Affiliation(s)
- Samarth Vadia
- Fakultät
für Physik, Munich Quantum Center, and Center for NanoScience
(CeNS), Ludwig-Maximilians-Universität
München, Geschwister-Scholl-Platz
1, 80539 München, Germany
- Munich
Center for Quantum Science and Technology (MCQST), Schellingtr. 4, 80799 München, Germany
- attocube
systems AG, Eglfinger
Weg 2, 85540 Haar, Germany
| | - Johannes Scherzer
- Fakultät
für Physik, Munich Quantum Center, and Center for NanoScience
(CeNS), Ludwig-Maximilians-Universität
München, Geschwister-Scholl-Platz
1, 80539 München, Germany
| | - Kenji Watanabe
- Research
Center for Functional Materials, National
Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- International
Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Alexander Högele
- Fakultät
für Physik, Munich Quantum Center, and Center for NanoScience
(CeNS), Ludwig-Maximilians-Universität
München, Geschwister-Scholl-Platz
1, 80539 München, Germany
- Munich
Center for Quantum Science and Technology (MCQST), Schellingtr. 4, 80799 München, Germany
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16
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Temperature induced modulation of resonant Raman scattering in bilayer 2H-MoS2. Sci Rep 2022; 12:14169. [PMID: 35986062 PMCID: PMC9391345 DOI: 10.1038/s41598-022-18439-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 08/11/2022] [Indexed: 11/15/2022] Open
Abstract
The temperature evolution of the resonant Raman scattering from high-quality bilayer 2H-MoS\documentclass[12pt]{minimal}
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\begin{document}$$\Gamma$$\end{document}Γ). The temperature evolution of the Raman scattering spectrum brings forward key observations, as the integrated intensity profiles of different phonon modes show diverse trends. The Raman-active A\documentclass[12pt]{minimal}
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17
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Salvador AG, Kuhlenkamp C, Ciorciaro L, Knap M, İmamoğlu A. Optical Signatures of Periodic Magnetization: The Moiré Zeeman Effect. PHYSICAL REVIEW LETTERS 2022; 128:237401. [PMID: 35749170 DOI: 10.1103/physrevlett.128.237401] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 04/22/2022] [Indexed: 06/15/2023]
Abstract
Detecting magnetic order at the nanoscale is of central interest for the study of quantum magnetism in general, and the emerging field of moiré magnets in particular. Here, we analyze the exciton band structure that arises from a periodic modulation of the valley Zeeman effect. Despite long-range electron-hole exchange interactions, we find a sizable splitting in the energy of the bright circularly polarized exciton Umklapp resonances, which serves as a direct optical probe of magnetic order. We first analyze quantum moiré magnets realized by periodic ordering of electron spins in Mott-Wigner states of transition metal dichalcogenide monolayers or twisted bilayers: we show that spin valley-dependent exciton-electron interactions allow for probing the spin-valley order of electrons and demonstrate that it is possible to observe unique signatures of ferromagnetic order in a triangular lattice and both ferromagnetic and Néel order in a honeycomb lattice. We then focus on semiclassical moiré magnets realized in twisted bilayers of ferromagnetic materials: we propose a detection scheme for moiré magnetism that is based on interlayer exchange coupling between spins in a moiré magnet and excitons in a transition metal dichalcogenide monolayer.
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Affiliation(s)
| | - Clemens Kuhlenkamp
- Institute for Quantum Electronics, ETH Zürich, CH-8093 Zürich, Switzerland
- Department of Physics, Technical University of Munich, 85748 Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), Schellingstr. 4, D-80799 München, Germany
| | - Livio Ciorciaro
- Institute for Quantum Electronics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Michael Knap
- Department of Physics, Technical University of Munich, 85748 Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), Schellingstr. 4, D-80799 München, Germany
| | - Ataç İmamoğlu
- Institute for Quantum Electronics, ETH Zürich, CH-8093 Zürich, Switzerland
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18
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Wang QH, Bedoya-Pinto A, Blei M, Dismukes AH, Hamo A, Jenkins S, Koperski M, Liu Y, Sun QC, Telford EJ, Kim HH, Augustin M, Vool U, Yin JX, Li LH, Falin A, Dean CR, Casanova F, Evans RFL, Chshiev M, Mishchenko A, Petrovic C, He R, Zhao L, Tsen AW, Gerardot BD, Brotons-Gisbert M, Guguchia Z, Roy X, Tongay S, Wang Z, Hasan MZ, Wrachtrup J, Yacoby A, Fert A, Parkin S, Novoselov KS, Dai P, Balicas L, Santos EJG. The Magnetic Genome of Two-Dimensional van der Waals Materials. ACS NANO 2022; 16:6960-7079. [PMID: 35442017 PMCID: PMC9134533 DOI: 10.1021/acsnano.1c09150] [Citation(s) in RCA: 68] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 02/23/2022] [Indexed: 05/23/2023]
Abstract
Magnetism in two-dimensional (2D) van der Waals (vdW) materials has recently emerged as one of the most promising areas in condensed matter research, with many exciting emerging properties and significant potential for applications ranging from topological magnonics to low-power spintronics, quantum computing, and optical communications. In the brief time after their discovery, 2D magnets have blossomed into a rich area for investigation, where fundamental concepts in magnetism are challenged by the behavior of spins that can develop at the single layer limit. However, much effort is still needed in multiple fronts before 2D magnets can be routinely used for practical implementations. In this comprehensive review, prominent authors with expertise in complementary fields of 2D magnetism (i.e., synthesis, device engineering, magneto-optics, imaging, transport, mechanics, spin excitations, and theory and simulations) have joined together to provide a genome of current knowledge and a guideline for future developments in 2D magnetic materials research.
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Affiliation(s)
- Qing Hua Wang
- Materials
Science and Engineering, School for Engineering of Matter, Transport
and Energy, Arizona State University, Tempe, Arizona 85287, United States
| | - Amilcar Bedoya-Pinto
- NISE
Department, Max Planck Institute of Microstructure
Physics, 06120 Halle, Germany
- Instituto
de Ciencia Molecular (ICMol), Universitat
de València, 46980 Paterna, Spain
| | - Mark Blei
- Materials
Science and Engineering, School for Engineering of Matter, Transport
and Energy, Arizona State University, Tempe, Arizona 85287, United States
| | - Avalon H. Dismukes
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
| | - Assaf Hamo
- Department
of Physics, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Sarah Jenkins
- Twist
Group,
Faculty of Physics, University of Duisburg-Essen, Campus Duisburg, 47057 Duisburg, Germany
| | - Maciej Koperski
- Institute
for Functional Intelligent Materials, National
University of Singapore, 117544 Singapore
| | - Yu Liu
- Condensed
Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Qi-Chao Sun
- Physikalisches
Institut, University of Stuttgart, 70569 Stuttgart, Germany
| | - Evan J. Telford
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
- Department
of Physics, Columbia University, New York, New York 10027, United States
| | - Hyun Ho Kim
- School
of Materials Science and Engineering, Department of Energy Engineering
Convergence, Kumoh National Institute of
Technology, Gumi 39177, Korea
| | - Mathias Augustin
- Institute
for Condensed Matter Physics and Complex Systems, School of Physics
and Astronomy, The University of Edinburgh, Edinburgh, EH9 3FD, United Kingdom
- Donostia
International Physics Center (DIPC), 20018 Donostia-San Sebastián, Basque Country, Spain
| | - Uri Vool
- Department
of Physics, Harvard University, Cambridge, Massachusetts 02138, United States
- John Harvard
Distinguished Science Fellows Program, Harvard
University, Cambridge, Massachusetts 02138, United States
| | - Jia-Xin Yin
- Laboratory
for Topological Quantum Matter and Spectroscopy, Department of Physics, Princeton University, Princeton, New Jersey 08544, United States
| | - Lu Hua Li
- Institute
for Frontier Materials, Deakin University, Geelong Waurn Ponds Campus, Waurn Ponds, Victoria 3216, Australia
| | - Alexey Falin
- Institute
for Frontier Materials, Deakin University, Geelong Waurn Ponds Campus, Waurn Ponds, Victoria 3216, Australia
| | - Cory R. Dean
- Department
of Physics, Columbia University, New York, New York 10027, United States
| | - Fèlix Casanova
- CIC nanoGUNE
BRTA, 20018 Donostia - San Sebastián, Basque
Country, Spain
- IKERBASQUE,
Basque Foundation for Science, 48013 Bilbao, Basque Country, Spain
| | - Richard F. L. Evans
- Department
of Physics, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Mairbek Chshiev
- Université
Grenoble Alpes, CEA, CNRS, Spintec, 38000 Grenoble, France
- Institut
Universitaire de France, 75231 Paris, France
| | - Artem Mishchenko
- Department
of Physics and Astronomy, University of
Manchester, Manchester, M13 9PL, United Kingdom
- National
Graphene Institute, University of Manchester, Manchester, M13 9PL, United Kingdom
| | - Cedomir Petrovic
- Condensed
Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Rui He
- Department
of Electrical and Computer Engineering, Texas Tech University, 910 Boston Avenue, Lubbock, Texas 79409, United
States
| | - Liuyan Zhao
- Department
of Physics, University of Michigan, 450 Church Street, Ann Arbor, Michigan 48109, United States
| | - Adam W. Tsen
- Institute
for Quantum Computing and Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Brian D. Gerardot
- SUPA, Institute
of Photonics and Quantum Sciences, Heriot-Watt
University, Edinburgh EH14 4AS, United Kingdom
| | - Mauro Brotons-Gisbert
- SUPA, Institute
of Photonics and Quantum Sciences, Heriot-Watt
University, Edinburgh EH14 4AS, United Kingdom
| | - Zurab Guguchia
- Laboratory
for Muon Spin Spectroscopy, Paul Scherrer
Institute, CH-5232 Villigen PSI, Switzerland
| | - Xavier Roy
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
| | - Sefaattin Tongay
- Materials
Science and Engineering, School for Engineering of Matter, Transport
and Energy, Arizona State University, Tempe, Arizona 85287, United States
| | - Ziwei Wang
- Department
of Physics and Astronomy, University of
Manchester, Manchester, M13 9PL, United Kingdom
- National
Graphene Institute, University of Manchester, Manchester, M13 9PL, United Kingdom
| | - M. Zahid Hasan
- Materials
Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
- Princeton
Institute for Science and Technology of Materials, Princeton University, Princeton, New Jersey 08544, United States
- National
High Magnetic Field Laboratory, Florida
State University, Tallahassee, Florida 32310, United States
| | - Joerg Wrachtrup
- Physikalisches
Institut, University of Stuttgart, 70569 Stuttgart, Germany
- Max Planck
Institute for Solid State Research, 70569 Stuttgart, Germany
| | - Amir Yacoby
- Department
of Physics, Harvard University, Cambridge, Massachusetts 02138, United States
- John A.
Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Albert Fert
- Donostia
International Physics Center (DIPC), 20018 Donostia-San Sebastián, Basque Country, Spain
- Unité
Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
- Department
of Materials Physics UPV/EHU, 20018 Donostia - San Sebastián, Basque Country, Spain
| | - Stuart Parkin
- NISE
Department, Max Planck Institute of Microstructure
Physics, 06120 Halle, Germany
| | - Kostya S. Novoselov
- Institute
for Functional Intelligent Materials, National
University of Singapore, 117544 Singapore
| | - Pengcheng Dai
- Department
of Physics and Astronomy, Rice University, Houston, Texas 77005, United States
| | - Luis Balicas
- National
High Magnetic Field Laboratory, Florida
State University, Tallahassee, Florida 32310, United States
- Department
of Physics, Florida State University, Tallahassee, Florida 32306, United States
| | - Elton J. G. Santos
- Institute
for Condensed Matter Physics and Complex Systems, School of Physics
and Astronomy, The University of Edinburgh, Edinburgh, EH9 3FD, United Kingdom
- Donostia
International Physics Center (DIPC), 20018 Donostia-San Sebastián, Basque Country, Spain
- Higgs Centre
for Theoretical Physics, The University
of Edinburgh, Edinburgh EH9 3FD, United Kingdom
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19
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Voroshnin V, Tarasov AV, Bokai KA, Chikina A, Senkovskiy BV, Ehlen N, Usachov DY, Grüneis A, Krivenkov M, Sánchez-Barriga J, Fedorov A. Direct Spectroscopic Evidence of Magnetic Proximity Effect in MoS 2 Monolayer on Graphene/Co. ACS NANO 2022; 16:7448-7456. [PMID: 35442015 DOI: 10.1021/acsnano.1c10391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
A magnetic field modifies optical properties and provides valley splitting in a molybdenum disulfide (MoS2) monolayer. Here we demonstrate a scalable approach to the epitaxial synthesis of MoS2 monolayer on a magnetic graphene/Co system. Using spin- and angle-resolved photoemission spectroscopy we observe a magnetic proximity effect that causes a 20 meV spin-splitting at the Γ̅ point and canting of spins at the K̅ point in the valence band toward the in-plane direction of cobalt magnetization. Our density functional theory calculations reveal that the in-plane spin component at K̅ is localized on Co atoms in the valence band, while in the conduction band it is localized on the MoS2 layer. The calculations also predict a 16 meV spin-splitting at the Γ̅ point and 8 meV K̅-K'¯ valley asymmetry for an out-of-plane magnetization. These findings suggest control over optical transitions in MoS2 via Co magnetization. Our estimations show that the magnetic proximity effect is equivalent to the action of the magnetic field as large as 100 T.
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Affiliation(s)
- Vladimir Voroshnin
- Institut für Physik und Astronomie, Universität Potsdam, Karl-Liebknecht-Strasse 24/25, Potsdam 14476, Germany
| | - Artem V Tarasov
- St. Petersburg State University, St. Petersburg 198504, Russia
| | - Kirill A Bokai
- St. Petersburg State University, St. Petersburg 198504, Russia
| | - Alla Chikina
- Paul Scherrer Institute, Forschungsstrasse 111, Villigen PSI 5232, Switzerland
| | - Boris V Senkovskiy
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Strasse 77, Köln 50937, Germany
| | - Niels Ehlen
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Strasse 77, Köln 50937, Germany
| | | | - Alexander Grüneis
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Strasse 77, Köln 50937, Germany
| | - Maxim Krivenkov
- Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin 12489, Germany
| | | | - Alexander Fedorov
- IFW Dresden, Leibniz Institute for Solid State and Materials Research, D-01171, Dresden 01069, Germany
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20
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Yin T, Ulman KA, Liu S, Granados Del Águila A, Huang Y, Zhang L, Serra M, Sedmidubsky D, Sofer Z, Quek SY, Xiong Q. Chiral Phonons and Giant Magneto-Optical Effect in CrBr 3 2D Magnet. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2101618. [PMID: 34302389 DOI: 10.1002/adma.202101618] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 06/20/2021] [Indexed: 06/13/2023]
Abstract
Phonons with chirality determine the optical helicity of inelastic light scattering processes due to their nonzero angular momentum. Here it is shown that 2D magnetic CrBr3 hosts chiral phonons at the Brillouin-zone center. These chiral phonons are linear combinations of the doubly-degenerate Eg phonons, and the phonon eigenmodes exhibit clockwise and counterclockwise rotational vibrations corresponding to angular momenta of l = ± 1. Such Eg chiral phonons completely switch the polarization of incident circularly polarized light. On the other hand, the non-degenerate non-chiral Ag phonons display a giant magneto-optical effect under an external out-of-plane magnetic field, rotating the plane of polarization of the scattered linearly polarized light. The corresponding degree of polarization of the scattered light changes from 91% to -68% as the magnetic field strength increases from 0 to 5 T. In contrast, the chiral Eg modes display no field dependence. The results lay a foundation for the study of phonon chirality and magneto-optical phenomena in 2D magnetic materials, as well as their related applications, such as the phonon Hall effect, topological photonics, and Raman lasing.
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Affiliation(s)
- Tingting Yin
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
| | - Kanchan Ajit Ulman
- Centre for Advanced 2D Materials, National University of Singapore, 6 Science Drive 2, Singapore, 117546, Singapore
| | - Sheng Liu
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
| | - Andrés Granados Del Águila
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
| | - Yuqing Huang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
| | - Lifa Zhang
- NNU-SULI Thermal Energy Research Center and Center for Quantum Transport and Thermal Energy Science, School of Physics and Technology, Nanjing Normal University, Nanjing, China
| | - Marco Serra
- University of Chemistry and Technology Prague, Technicka 5, Prague, 16628, Czech Republic
| | - David Sedmidubsky
- University of Chemistry and Technology Prague, Technicka 5, Prague, 16628, Czech Republic
| | - Zdenek Sofer
- University of Chemistry and Technology Prague, Technicka 5, Prague, 16628, Czech Republic
| | - Su Ying Quek
- Centre for Advanced 2D Materials, National University of Singapore, 6 Science Drive 2, Singapore, 117546, Singapore
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117542, Singapore
- NUS Graduate School, Integrative Sciences and Engineering Programme, National University of Singapore, Singapore, 117456, Singapore
- Department of Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore, 117575, Singapore
| | - Qihua Xiong
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, 100084, P. R. China
- Beijing Academy of Quantum Information Sciences, Beijing, 100193, P. R. China
- Beijing Innovation Center for Future Chips, Tsinghua University, Beijing, 100084, P. R. China
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21
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Grzeszczyk M, Szpakowski J, Slobodeniuk AO, Kazimierczuk T, Bhatnagar M, Taniguchi T, Watanabe K, Kossacki P, Potemski M, Babiński A, Molas MR. The optical response of artificially twisted MoS[Formula: see text] bilayers. Sci Rep 2021; 11:17037. [PMID: 34426607 PMCID: PMC8382769 DOI: 10.1038/s41598-021-95700-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 07/27/2021] [Indexed: 11/17/2022] Open
Abstract
Two-dimensional layered materials offer the possibility to create artificial vertically stacked structures possessing an additional degree of freedom-the interlayer twist. We present a comprehensive optical study of artificially stacked bilayers (BLs) MoS[Formula: see text] encapsulated in hexagonal BN with interlayer twist angle ranging from 0[Formula: see text] to 60[Formula: see text] using Raman scattering and photoluminescence spectroscopies. It is found that the strength of the interlayer coupling in the studied BLs can be estimated using the energy dependence of indirect emission versus the A[Formula: see text]-E[Formula: see text] energy separation. Due to the hybridization of electronic states in the valence band, the emission line related to the interlayer exciton is apparent in both the natural (2H) and artificial (62[Formula: see text]) MoS[Formula: see text] BLs, while it is absent in the structures with other twist angles. The interlayer coupling energy is estimated to be of about 50 meV. The effect of temperature on energies and intensities of the direct and indirect emission lines in MoS[Formula: see text] BLs is also quantified.
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Affiliation(s)
- M. Grzeszczyk
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - J. Szpakowski
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - A. O. Slobodeniuk
- Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague 2, Czech Republic
| | - T. Kazimierczuk
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - M. Bhatnagar
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - T. Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044 Japan
| | - K. Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044 Japan
| | - P. Kossacki
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - M. Potemski
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25, Avenue des Martyrs, 38042 Grenoble, France
| | - A. Babiński
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - M. R. Molas
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
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22
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Tiessen J, Shi J. Nano-chevron quantum dot for spin-qubit applications. NANOSCALE 2021; 13:12659-12668. [PMID: 34477616 DOI: 10.1039/d1nr02842a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We study the theoretical properties of a parabolic hBN/MoS2/hBN heterostructure quantum dot potential generated via electrostatic gates and its interaction with a cobalt nano chevron. We demonstrate that such an example system can undergo electric dipole spin resonance for a single electron isolated to the K' valley within the MoS2 monolayer, and such a system can achieve pi-rotation times of approximately 5.5 ns under the influence of a 20.89 GHz driving field. Our proposed system requires operating conditions easily achievable with current experimental methods and would allow for the all-electrical control of a spin-qubit within an MoS2 device. Our results show that such a system is experimentally feasible and would have comparable properties to that of more traditional silicon based spin-qubits. Furthermore, the design of the device can be applied to other material systems beyond MoS2 and cobalt. In theory, the proposed structure could make use of any 2D material that experiences strong proximity exchange interactions with other magnetic materials, which makes our proposed design highly general.
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Affiliation(s)
- John Tiessen
- Department of Electrical and Computer Engineering, University of Illinois at Chicago, Chicago, IL 60607, USA.
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23
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Heißenbüttel MC, Deilmann T, Krüger P, Rohlfing M. Valley-Dependent Interlayer Excitons in Magnetic WSe 2/CrI 3. NANO LETTERS 2021; 21:5173-5178. [PMID: 34077218 DOI: 10.1021/acs.nanolett.1c01232] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Heterostructures of two-dimensional transition-metal dichalcogenides and ferromagnetic substrates are important candidates for the development of viable new spin- or valleytronic devices. For the prototypical bilayer of WSe2 on top of a ferromagnetic layer of CrI3, we find substantially different coupling of both WSe2 K-valleys to the sublayer. Besides an energy splitting of a few meV, the corresponding excitons have significantly different interlayer character with charge transfer allowed at the K̅- point but forbidden at K̅+. The different exciton wave functions result in a distinctly different response to magnetic fields with g factors of about -4.4 and -4.0, respectively. By means of ab initio GW/Bethe-Salpeter equation calculations, these findings establish g factors as tool for investigating the exciton character and shedding light on the detailed quantum-mechanical interplay of magnetic and optical properties which are essential for the targeted development of optoelectronic devices.
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Affiliation(s)
| | - Thorsten Deilmann
- Institut für Festkörpertheorie, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Peter Krüger
- Institut für Festkörpertheorie, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Michael Rohlfing
- Institut für Festkörpertheorie, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
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24
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Liu H, Fu D, Li X, Han J, Chen X, Wu X, Sun B, Tang W, Ke C, Wu Y, Wu Z, Kang J. Enhanced Valley Splitting in Monolayer WSe 2 by Phase Engineering. ACS NANO 2021; 15:8244-8251. [PMID: 33982558 DOI: 10.1021/acsnano.0c08305] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Lifting the valley degeneracy in two-dimensional transition metal dichalcogenides could promote their applications in information processing. Various external regulations, including magnetic substrate, magnetic doping, electric field, and carrier doping, have been implemented to enhance the valley splitting under the magnetic field. Here, a phase engineering strategy, through modifying the intrinsic lattice structure, is proposed to enhance the valley splitting in monolayer WSe2. The valley splitting in hybrid H and T phase WSe2 is tunable by the concentration of the T phase. An obvious valley splitting of ∼4.1 meV is obtained with the T phase concentration of 31% under ±5 T magnetic fields, which corresponds to an effective Landé geff factor of -14, about 3.5-fold of that in pure H-WSe2. Comparing the temperature and magnetic field dependent polarized photoluminescence and also combining the theoretical simulations reveal the enhanced valley splitting is dominantly attributed to exchange interaction of H phase WSe2 with the local magnetic moments induced by the T phase. This finding provides a convenient solution for lifting the valley degeneracy of two-dimensional materials.
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Affiliation(s)
- Haiyang Liu
- Department of Physics, OSED, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Xiamen University, Xiamen 361005, People's Republic of China
| | - Deyi Fu
- Department of Physics, OSED, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Xiamen University, Xiamen 361005, People's Republic of China
| | - Xu Li
- Department of Physics, OSED, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Xiamen University, Xiamen 361005, People's Republic of China
| | - Junbo Han
- Wuhan National High Magnetic Field Center and School of Physics, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
| | - Xiaodie Chen
- Wuhan National High Magnetic Field Center and School of Physics, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
| | - Xuefeng Wu
- Department of Physics, OSED, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Xiamen University, Xiamen 361005, People's Republic of China
| | - Baofan Sun
- Department of Physics, OSED, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Xiamen University, Xiamen 361005, People's Republic of China
| | - Weiqing Tang
- Department of Physics, OSED, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Xiamen University, Xiamen 361005, People's Republic of China
| | - Congming Ke
- Department of Physics, OSED, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Xiamen University, Xiamen 361005, People's Republic of China
| | - Yaping Wu
- Department of Physics, OSED, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Xiamen University, Xiamen 361005, People's Republic of China
| | - Zhiming Wu
- Department of Physics, OSED, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Xiamen University, Xiamen 361005, People's Republic of China
| | - Junyong Kang
- Department of Physics, OSED, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Xiamen University, Xiamen 361005, People's Republic of China
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25
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Miao N, Sun Z. Computational design of two‐dimensional magnetic materials. WIRES COMPUTATIONAL MOLECULAR SCIENCE 2021. [DOI: 10.1002/wcms.1545] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Naihua Miao
- School of Materials Science and Engineering Beihang University Beijing China
- Center for Integrated Computational Materials Engineering International Research Institute for Multidisciplinary Science, Beihang University Beijing China
| | - Zhimei Sun
- School of Materials Science and Engineering Beihang University Beijing China
- Center for Integrated Computational Materials Engineering International Research Institute for Multidisciplinary Science, Beihang University Beijing China
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26
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Sun QC, Song T, Anderson E, Brunner A, Förster J, Shalomayeva T, Taniguchi T, Watanabe K, Gräfe J, Stöhr R, Xu X, Wrachtrup J. Magnetic domains and domain wall pinning in atomically thin CrBr 3 revealed by nanoscale imaging. Nat Commun 2021; 12:1989. [PMID: 33790290 PMCID: PMC8012586 DOI: 10.1038/s41467-021-22239-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 03/03/2021] [Indexed: 11/09/2022] Open
Abstract
The emergence of atomically thin van der Waals magnets provides a new platform for the studies of two-dimensional magnetism and its applications. However, the widely used measurement methods in recent studies cannot provide quantitative information of the magnetization nor achieve nanoscale spatial resolution. These capabilities are essential to explore the rich properties of magnetic domains and spin textures. Here, we employ cryogenic scanning magnetometry using a single-electron spin of a nitrogen-vacancy center in a diamond probe to unambiguously prove the existence of magnetic domains and study their dynamics in atomically thin CrBr3. By controlling the magnetic domain evolution as a function of magnetic field, we find that the pinning effect is a dominant coercivity mechanism and determine the magnetization of a CrBr3 bilayer to be about 26 Bohr magnetons per square nanometer. The high spatial resolution of this technique enables imaging of magnetic domains and allows to locate the sites of defects that pin the domain walls and nucleate the reverse domains. Our work highlights scanning nitrogen-vacancy center magnetometry as a quantitative probe to explore nanoscale features in two-dimensional magnets. Van der Waals (vdW) magnets have allowed researchers to explore the two dimensional limit of magnetisation; however experimental challenges have hindered analysis of magnetic domains. Here, using an NV centre based probe, the authors analyse the nature of magnetic domains in the vdW magnet, CrBr3.
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Affiliation(s)
- Qi-Chao Sun
- 3. Physikalisches Institut, University of Stuttgart, Stuttgart, Germany.
| | - Tiancheng Song
- Department of Physics, University of Washington, Seattle, WA, USA
| | - Eric Anderson
- Department of Physics, University of Washington, Seattle, WA, USA
| | - Andreas Brunner
- 3. Physikalisches Institut, University of Stuttgart, Stuttgart, Germany
| | - Johannes Förster
- Max Planck Institute for Intelligent Systems, Stuttgart, Germany
| | | | | | - Kenji Watanabe
- National Institute for Materials Science, Tsukuba, Ibaraki, Japan
| | - Joachim Gräfe
- Max Planck Institute for Intelligent Systems, Stuttgart, Germany
| | - Rainer Stöhr
- 3. Physikalisches Institut, University of Stuttgart, Stuttgart, Germany. .,Center for Applied Quantum Technology, University of Stuttgart, Stuttgart, Germany.
| | - Xiaodong Xu
- Department of Physics, University of Washington, Seattle, WA, USA.,Department of Materials Science and Engineering, University of Washington, Seattle, WA, USA
| | - Jörg Wrachtrup
- 3. Physikalisches Institut, University of Stuttgart, Stuttgart, Germany.,Max Planck Institute for Solid State Research, Stuttgart, Germany
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27
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Wu D, Zhuo Z, Lv H, Wu X. Two-Dimensional Cr 2X 3S 3 (X = Br, I) Janus Semiconductor with Intrinsic Room-Temperature Magnetism. J Phys Chem Lett 2021; 12:2905-2911. [PMID: 33725451 DOI: 10.1021/acs.jpclett.1c00454] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The exploration of two-dimensional (2D) semiconductors with intrinsic room-temperature magnetism for use in nanoscale spintronic devices is of particular interest. Recently, the ferromagnetic CrX3 monolayer (X = Br, I) has received growing attention, but low critical temperature hinders its practical applications in spintronics. Here, using first-principles calculations, we report 2D Cr2X3S3 (X = Br, I) Janus semiconductors with room-temperature magnetism by replacing one layer of halogon atoms with sulfur atoms in CrX3 monolayer. Our results demonstrate that Cr2Br3S3 and Cr2I3S3 Janus crystals are ferrimagnetic semiconductors, that maintain their magnetic order, with a direct bandgap of 1.19 and 0.61 eV and high critical temperature of 387 and 447 K, respectively. The residual unpaired p electrons on the S anions lead to a strong direct-exchange interaction between the Cr and S atoms. Moreover, their room-temperature magnetism is robust under biaxial strain, while the bandgap can be remarkably modulated with strain. The novel magnetic properties in 2D Cr2X3S3 Janus magnetic semiconductors give them promising applications in spintronics.
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Affiliation(s)
- Daoxiong Wu
- Hefei National Laboratory for Physical Sciences at the Microscale, School of Chemistry and Materials Sciences, CAS Key Laboratory of Materials for Energy Conversion, and CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Zhiwen Zhuo
- Hefei National Laboratory for Physical Sciences at the Microscale, School of Chemistry and Materials Sciences, CAS Key Laboratory of Materials for Energy Conversion, and CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Haifeng Lv
- Hefei National Laboratory for Physical Sciences at the Microscale, School of Chemistry and Materials Sciences, CAS Key Laboratory of Materials for Energy Conversion, and CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xiaojun Wu
- Hefei National Laboratory for Physical Sciences at the Microscale, School of Chemistry and Materials Sciences, CAS Key Laboratory of Materials for Energy Conversion, and CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei, Anhui 230026, China
- Synergetic Innovation of Quantum Information & Quantum Technology, University of Science and Technology of China, Hefei, Anhui 230026, China
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28
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Lyons TP, Gillard D, Molina-Sánchez A, Misra A, Withers F, Keatley PS, Kozikov A, Taniguchi T, Watanabe K, Novoselov KS, Fernández-Rossier J, Tartakovskii AI. Interplay between spin proximity effect and charge-dependent exciton dynamics in MoSe 2/CrBr 3 van der Waals heterostructures. Nat Commun 2020; 11:6021. [PMID: 33244001 PMCID: PMC7691354 DOI: 10.1038/s41467-020-19816-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 10/30/2020] [Indexed: 11/18/2022] Open
Abstract
Semiconducting ferromagnet-nonmagnet interfaces in van der Waals heterostructures present a unique opportunity to investigate magnetic proximity interactions dependent upon a multitude of phenomena including valley and layer pseudospins, moiré periodicity, or exceptionally strong Coulomb binding. Here, we report a charge-state dependency of the magnetic proximity effects between MoSe2 and CrBr3 in photoluminescence, whereby the valley polarization of the MoSe2 trion state conforms closely to the local CrBr3 magnetization, while the neutral exciton state remains insensitive to the ferromagnet. We attribute this to spin-dependent interlayer charge transfer occurring on timescales between the exciton and trion radiative lifetimes. Going further, we uncover by both the magneto-optical Kerr effect and photoluminescence a domain-like spatial topography of contrasting valley polarization, which we infer to be labyrinthine or otherwise highly intricate, with features smaller than 400 nm corresponding to our optical resolution. Our findings offer a unique insight into the interplay between short-lived valley excitons and spin-dependent interlayer tunneling, while also highlighting MoSe2 as a promising candidate to optically interface with exotic spin textures in van der Waals structures.
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Affiliation(s)
- T P Lyons
- Department of Physics and Astronomy, The University of Sheffield, Sheffield, S3 7RH, UK.
| | - D Gillard
- Department of Physics and Astronomy, The University of Sheffield, Sheffield, S3 7RH, UK
| | - A Molina-Sánchez
- QuantaLab, International Iberian Nanotechnology Laboratory, Braga, 4715-330, Portugal
| | - A Misra
- School of Physics and Astronomy, The University of Manchester, Manchester, M13 9PL, UK
- Department of Physics, Indian Institute of Technology Madras (IIT Madras), Chennai, India
| | - F Withers
- Department of Physics and Astronomy, University of Exeter, Exeter, EX4 4QL, UK
| | - P S Keatley
- Department of Physics and Astronomy, University of Exeter, Exeter, EX4 4QL, UK
| | - A Kozikov
- School of Physics and Astronomy, The University of Manchester, Manchester, M13 9PL, UK
| | - T Taniguchi
- National Institute for Materials Science, Tsukuba, Ibaraki, 305-0044, Japan
| | - K Watanabe
- National Institute for Materials Science, Tsukuba, Ibaraki, 305-0044, Japan
| | - K S Novoselov
- School of Physics and Astronomy, The University of Manchester, Manchester, M13 9PL, UK
- Centre for Advanced 2D Materials, National University of Singapore, Singapore, 117546, Singapore
- Chongqing 2D Materials Institute, Liangjiang New Area, Chongqing, 400714, China
| | - J Fernández-Rossier
- QuantaLab, International Iberian Nanotechnology Laboratory, Braga, 4715-330, Portugal
| | - A I Tartakovskii
- Department of Physics and Astronomy, The University of Sheffield, Sheffield, S3 7RH, UK.
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Soriano D, Katsnelson MI, Fernández-Rossier J. Magnetic Two-Dimensional Chromium Trihalides: A Theoretical Perspective. NANO LETTERS 2020; 20:6225-6234. [PMID: 32787171 DOI: 10.1021/acs.nanolett.0c02381] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The discovery of ferromagnetic order in monolayer two-dimensional (2D) crystals has opened a new venue in the field of 2D materials. Two-dimensional magnets are not only interesting on their own, but their integration in van der Waals heterostructures allows for the observation of new and exotic effects in the ultrathin limit. The family of chromium trihalides, CrI3, CrBr3, and CrCl3, is so far the most studied among magnetic 2D crystals. In this Mini Review, we provide a perspective of the state of the art of the theoretical understanding of magnetic 2D trihalides, most of which will also be relevant for other 2D magnets, such as vanadium trihalides. We discuss both the well-established facts, such as the origin of the magnetic moment and magnetic anisotropy, and address as well open issues such as the nature of the anisotropic spin couplings and the magnitude of the magnon gap. Recent theoretical predictions on Moiré magnets and magnetic skyrmions are also discussed. Finally, we give some prospects about the future interest of these materials and possible device applications.
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Affiliation(s)
- D Soriano
- Institute for Molecules and Materials, Radboud University, NL-6525 AJ Nijmegen, The Netherlands
| | - M I Katsnelson
- Institute for Molecules and Materials, Radboud University, NL-6525 AJ Nijmegen, The Netherlands
| | - J Fernández-Rossier
- QuantaLab, International Iberian Nanotechnology Laboratory (INL), Avenido Mestre José Veiga, 4715-330 Braga, Portugal
- Departamento de Física Aplicada, Universidad de Alicante, 03690, Alicante, Spain
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