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Wang Z, Han X, Liang Y. Large valley splitting and vacancy-induced valley polarization in two-dimensional WSeNH. Phys Chem Chem Phys 2024; 26:17148-17154. [PMID: 38847342 DOI: 10.1039/d4cp01533a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/20/2024]
Abstract
The investigation and manipulation of valley pseudospin in promising two-dimensional (2D) semiconductors are essential for accelerating the development of valleytronics. Based on first-principles, we herein report that the WSeNH monolayer is a potential 2D valleytronic material. It is found that stable 2D WSeNH exhibits a semiconducting character with broken inversion symmetry, forming a pair of energy-degenerate but inequivalent valleys at the K and K' points. Arising from the strong spin-orbit coupling strength governed by the W-dxy/dx2-y2 orbitals, it exhibits a large valley splitting of 425 meV at the top of the valence band, which makes it highly plausible for generating the attractive valley Hall effect. Moreover, both valley splitting and optical transition energy can be efficiently modulated by external strain. Furthermore, we find that a considerable valley polarization of 23 meV can be readily realized in 2D WSeNH by introducing hydrogen vacancies. These findings not only broaden the family of 2D valleytronic materials but also provide alternative avenues for valley manipulation.
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Affiliation(s)
- Ziqi Wang
- College of Physics and Optoelectronic Engineering, Faculty of Information Science and Engineering, Ocean University of China, Qingdao 266100, People's Republic of China.
| | - Xuening Han
- College of Physics and Optoelectronic Engineering, Faculty of Information Science and Engineering, Ocean University of China, Qingdao 266100, People's Republic of China.
| | - Yan Liang
- College of Physics and Optoelectronic Engineering, Faculty of Information Science and Engineering, Ocean University of China, Qingdao 266100, People's Republic of China.
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2
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Liu Z, Zhou B, Wang X. Two-dimensional multiferroic RuClF/AgBiP 2S 6 van der Waals heterostructures with valley splitting properties and controllable magnetic anisotropy. Phys Chem Chem Phys 2024. [PMID: 38887794 DOI: 10.1039/d4cp01059k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/20/2024]
Abstract
The investigation of new properties in two-dimensional (2D) multiferroic heterostructures is significant. In this work, the electronic properties and magnetic anisotropy energies (MAEs) of 2D multiferroic RuClF/AgBiP2S6 van der Waals (vdW) heterostructures are systematically studied by first principles calculations based on density functional theory (DFT). The Hubbard on-site Coulomb parameter (U) of Ru atoms is necessary to account for the strong correlation among the three-dimensional electrons of Ru. RuClF/AgBiP2S6 heterostructures in different polarizations (RuClF/AgBiP2S6-P↑ and RuClF/AgBiP2S6-P↓) are ferromagnetic semiconductors with stable structures. Valley polarizations are present in the band structures of RuClF/AgBiP2S6 heterostructures with spin-orbit coupling (SOC), the valley splitting energies of which are 279 meV and 263 meV, respectively. The MAEs of RuClF/AgBiP2S6 heterostructures indicate perpendicular magnetic anisotropy (PMA), which are primarily attributed to the differences in matrix elements within Ru (dyz, dz2) orbitals. In addition, valley splittings and MAEs of RuClF/AgBiP2S6 heterostructures are modified at different biaxial strains. Specifically, the highest valley splittings are 283 meV and 287 meV at ε = 2%, while they disappear at ε = -6%. The PMA of RuClF/AgBiP2S6-P↑ is gradually decreased at biaxial strains of -6% to 2%, and MAE is transformed into in-plane magnetic anisotropy (IMA) at ε = 4%. RuClF/AgBiP2S6-P↓ maintains PMA at different strains. The study of non-volatile electrical control of valley splitting phenomena in multiferroic RuClF/AgBiP2S6 heterostructures is crucial in the field of valleytronic devices, which has important theoretical significance.
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Affiliation(s)
- Ziyu Liu
- 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.
| | - Xiaocha Wang
- 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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3
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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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4
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Liu H, Zhang Z, Zhang C, Li X, Zhang C, Xu F, Wu Y, Wu Z, Kang J. Simultaneously Regulated Highly Polarized and Long-Lived Valley Excitons in WSe 2/GaN Heterostructures. NANO LETTERS 2024; 24:1851-1858. [PMID: 38315876 DOI: 10.1021/acs.nanolett.3c03494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2024]
Abstract
Interlayer excitons, with prolonged lifetimes and tunability, hold potential for advanced optoelectronics. Previous research on the interlayer excitons has been dominated by two-dimensional heterostructures. Here, we construct WSe2/GaN composite heterostructures, in which the doping concentration of GaN and the twist angle of bilayer WSe2 are employed as two ingredients for the manipulation of exciton behaviors and polarizations. The exciton energies in monolayer WSe2/GaN can be regulated continuously by the doping levels of the GaN substrate, and a remarkable increase in the valley polarizations is achieved. Especially in a heterostructure with 4°-twisted bilayer WSe2, a maximum polarization of 38.9% with a long lifetime is achieved for the interlayer exciton. Theoretical calculations reveal that the large polarization and long lifetime are attributed to the high exciton binding energy and large spin flipping energy during depolarization in bilayer WSe2/GaN. This work introduces a distinctive member of the interlayer exciton with a high degree of polarization and a long lifetime.
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Affiliation(s)
- Haiyang Liu
- Department of Physics, Engineering Research Centre for Micro-Nano Optoelectronic Materials and Devices at Education Ministry, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Xiamen University, Xiamen 361005, P. R. China
- School of Physical Science and Technology, Wuhan University, Wuhan 430072, P. R. China
| | - Zongnan Zhang
- Department of Physics, Engineering Research Centre for Micro-Nano Optoelectronic Materials and Devices at Education Ministry, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Xiamen University, Xiamen 361005, P. R. China
| | - Chenhao Zhang
- Department of Physics, Engineering Research Centre for Micro-Nano Optoelectronic Materials and Devices at Education Ministry, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Xiamen University, Xiamen 361005, P. R. China
| | - Xu Li
- Department of Physics, Engineering Research Centre for Micro-Nano Optoelectronic Materials and Devices at Education Ministry, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Xiamen University, Xiamen 361005, P. R. China
| | - Chunmiao Zhang
- Department of Physics, Engineering Research Centre for Micro-Nano Optoelectronic Materials and Devices at Education Ministry, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Xiamen University, Xiamen 361005, P. R. China
| | - Feiya Xu
- Department of Physics, Engineering Research Centre for Micro-Nano Optoelectronic Materials and Devices at Education Ministry, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Xiamen University, Xiamen 361005, P. R. China
| | - Yaping Wu
- Department of Physics, Engineering Research Centre for Micro-Nano Optoelectronic Materials and Devices at Education Ministry, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Xiamen University, Xiamen 361005, P. R. China
| | - Zhiming Wu
- Department of Physics, Engineering Research Centre for Micro-Nano Optoelectronic Materials and Devices at Education Ministry, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Xiamen University, Xiamen 361005, P. R. China
| | - Junyong Kang
- Department of Physics, Engineering Research Centre for Micro-Nano Optoelectronic Materials and Devices at Education Ministry, Fujian Provincial Key Laboratory of Semiconductor Materials and Applications, Xiamen University, Xiamen 361005, P. R. China
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5
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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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6
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Zhang SH, Shao DF, Wang ZA, Yang J, Yang W, Tsymbal EY. Tunneling Valley Hall Effect Driven by Tilted Dirac Fermions. PHYSICAL REVIEW LETTERS 2023; 131:246301. [PMID: 38181146 DOI: 10.1103/physrevlett.131.246301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 11/21/2023] [Indexed: 01/07/2024]
Abstract
Valleytronics is a research field utilizing a valley degree of freedom of electrons for information processing and storage. A strong valley polarization is critical for realistic valleytronic applications. Here, we predict a tunneling valley Hall effect (TVHE) driven by tilted Dirac fermions in all-in-one tunnel junctions based on a two-dimensional (2D) valley material. Different doping of the electrode and spacer regions in these tunnel junctions results in momentum filtering of the tunneling Dirac fermions, generating a strong transverse valley Hall current dependent on the Dirac-cone tilting. Using the parameters of an existing 2D valley material, we demonstrate that such a strong TVHE can host a giant valley Hall angle even in the absence of the Berry curvature. Finally, we predict that resonant tunneling can occur in a tunnel junction with properly engineered device parameters such as the spacer width and transport direction, providing significant enhancement of the valley Hall angle. Our work opens a new approach to generate valley polarization in realistic valleytronic systems.
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Affiliation(s)
- Shu-Hui Zhang
- College of Mathematics and Physics, Beijing University of Chemical Technology, Beijing 100029, China
| | - Ding-Fu Shao
- Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China
| | - Zi-An Wang
- Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China
- University of Science and Technology of China, Hefei 230026, China
| | - Jin Yang
- Beijing Computational Science Research Center, Beijing 100193, China
| | - Wen Yang
- Beijing Computational Science Research Center, Beijing 100193, China
| | - Evgeny Y Tsymbal
- Department of Physics and Astronomy & Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, Nebraska 68588-0299, USA
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7
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Man P, Huang L, Zhao J, Ly TH. Ferroic Phases in Two-Dimensional Materials. Chem Rev 2023; 123:10990-11046. [PMID: 37672768 DOI: 10.1021/acs.chemrev.3c00170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/08/2023]
Abstract
Two-dimensional (2D) ferroics, namely ferroelectric, ferromagnetic, and ferroelastic materials, are attracting rising interest due to their fascinating physical properties and promising functional applications. A variety of 2D ferroic phases, as well as 2D multiferroics and the novel 2D ferrovalleytronics/ferrotoroidics, have been recently predicted by theory, even down to the single atomic layers. Meanwhile, some of them have already been experimentally verified. In addition to the intrinsic 2D ferroics, appropriate stacking, doping, and defects can also artificially regulate the ferroic phases of 2D materials. Correspondingly, ferroic ordering in 2D materials exhibits enormous potential for future high density memory devices, energy conversion devices, and sensing devices, among other applications. In this paper, the recent research progresses on 2D ferroic phases are comprehensively reviewed, with emphasis on chemistry and structural origin of the ferroic properties. In addition, the promising applications of the 2D ferroics for information storage, optoelectronics, and sensing are also briefly discussed. Finally, we envisioned a few possible pathways for the future 2D ferroics research and development. This comprehensive overview on the 2D ferroic phases can provide an atlas for this field and facilitate further exploration of the intriguing new materials and physical phenomena, which will generate tremendous impact on future functional materials and devices.
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Affiliation(s)
- Ping Man
- Department of Chemistry and Center of Super-Diamond & Advanced Films (COSDAF), City University of Hong Kong, Kowloon, Hong Kong 999077, P. R. China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, P. R. China
| | - Lingli Huang
- Department of Chemistry and Center of Super-Diamond & Advanced Films (COSDAF), City University of Hong Kong, Kowloon, Hong Kong 999077, P. R. China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, P. R. China
| | - Jiong Zhao
- Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong 999077, P. R. China
- The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen 518057, P. R. China
| | - Thuc Hue Ly
- Department of Chemistry and Center of Super-Diamond & Advanced Films (COSDAF), City University of Hong Kong, Kowloon, Hong Kong 999077, P. R. China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, P. R. China
- Department of Chemistry and State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon, Hong Kong 999077, P. R. China
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8
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Chiu CH, Chen YT, Shen JL. Quantum dots derived from two-dimensional transition metal dichalcogenides: synthesis, optical properties and optoelectronic applications. NANOTECHNOLOGY 2023; 34:482001. [PMID: 37607498 DOI: 10.1088/1361-6528/acf29c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 08/21/2023] [Indexed: 08/24/2023]
Abstract
Zero-dimensional transition metal dichalcogenides (TMD) quantum dots (QDs) have attracted a lot of attention due to their interesting fundamental properties and various applications. Compared to TMD monolayers, the QD counterpart exhibits larger values for direct transition energies, exciton binding energies, absorption coefficient, luminescence efficiency, and specific surface area. These characteristics make them useful in optoelectronic devices. In this review, recent exciting progress on synthesis, optical properties, and applications of TMD QDs is highlighted. The first part of this article begins with a brief description of the synthesis approaches, which focus on microwave-assistant heating and pulsed laser ablation methods. The second part introduces the fundamental optical properties of TMD QDs, including quantum confinement in optical absorption, excitation-wavelength-dependent photoluminescence, and many-body effects. These properties are highlighted. In the third part, we discuss lastest advancements in optoelectronic devices based on TMD QDs These devices include light-emitting diodes, solar cells, photodetectors, optical sensors, and light-controlled memory devices. Finally, a brief summary and outlook will be provided.
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Affiliation(s)
- Ching-Hsueh Chiu
- Department of Physics, Center for Nanotechnology, and Research Center for Crystalline Materials and Optoelectronic Characterization, Chung Yuan Christian University, Chung-Li, 320314, Taiwan
| | - Yu-Ting Chen
- Department of Physics, Center for Nanotechnology, and Research Center for Crystalline Materials and Optoelectronic Characterization, Chung Yuan Christian University, Chung-Li, 320314, Taiwan
| | - Ji-Lin Shen
- Department of Physics, Center for Nanotechnology, and Research Center for Crystalline Materials and Optoelectronic Characterization, Chung Yuan Christian University, Chung-Li, 320314, Taiwan
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9
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Singh S, Gong W, Stevens CE, Hou J, Singh A, Zhang H, Anantharaman SB, Mohite AD, Hendrickson JR, Yan Q, Jariwala D. Valley-Polarized Interlayer Excitons in 2D Chalcogenide-Halide Perovskite-van der Waals Heterostructures. ACS NANO 2023; 17:7487-7497. [PMID: 37010369 DOI: 10.1021/acsnano.2c12546] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Interlayer excitons (IXs) in two-dimensional (2D) heterostructures provide an exciting avenue for exploring optoelectronic and valleytronic phenomena. Presently, valleytronic research is limited to transition metal dichalcogenide (TMD) based 2D heterostructure samples, which require strict lattice (mis) match and interlayer twist angle requirements. Here, we explore a 2D heterostructure system with experimental observation of spin-valley layer coupling to realize helicity-resolved IXs, without the requirement of a specific geometric arrangement, i.e., twist angle or specific thermal annealing treatment of the samples in 2D Ruddlesden-Popper (2DRP) halide perovskite/2D TMD heterostructures. Using first-principle calculations, time-resolved and circularly polarized luminescence measurements, we demonstrate that Rashba spin-splitting in 2D perovskites and strongly coupled spin-valley physics in monolayer TMDs render spin-valley-dependent optical selection rules to the IXs. Consequently, a robust valley polarization of ∼14% with a long exciton lifetime of ∼22 ns is obtained in type-II band aligned 2DRP/TMD heterostructure at ∼1.54 eV measured at 80 K. Our work expands the scope for studying spin-valley physics in heterostructures of disparate classes of 2D semiconductors.
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Affiliation(s)
- Simrjit Singh
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
- Department of Applied Physics and Eindhoven Hendrik Casimir Institute, Eindhoven University of Technology, Eindhoven, 5612 AZ, The Netherlands
| | - Weiyi Gong
- Department of Physics, Northeastern University, Boston, Massachusetts 02115, United States
| | - Christopher E Stevens
- Sensors Directorate, Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433, United States
- KBR Inc., Beavercreek, Ohio 45431, United States
| | - Jin Hou
- Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, United States
| | - Aditya Singh
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Huiqin Zhang
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Surendra B Anantharaman
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Aditya D Mohite
- Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, United States
| | - Joshua R Hendrickson
- Sensors Directorate, Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433, United States
| | - Qimin Yan
- Department of Physics, Northeastern University, Boston, Massachusetts 02115, United States
| | - Deep Jariwala
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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10
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Jia K, Dong XJ, Li SS, Ji WX, Zhang CW. Spontaneous valley polarization and valley-nonequilibrium quantum anomalous Hall effect in Janus monolayer ScBrI. NANOSCALE 2023; 15:8395-8405. [PMID: 37092871 DOI: 10.1039/d2nr07221a] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Topology and ferrovalley (FV) are two essential concepts in emerging device applications and the fundamental research field. To date, relevant reports are extremely rare about the coupling of FV and topology in a single system. By Monte Carlo (MC) simulations and first-principles calculations, a stable intrinsic FV ScBrI semiconductor with high Curie temperature (TC) is predicted. Because of the combination of spin-orbital coupling (SOC) and exchange interaction, the Janus monolayer ScBrI shows a spontaneous valley polarization of 90 meV, which is located in the top valence band. For the magnetization direction perpendicular to the plane, the changes from FV to half-valley-metal (HVM), to valley-nonequilibrium quantum anomalous Hall effect (VQAHE), to HVM, and to FV can be induced by strain engineering. It is worth noting that there are no particular valley polarization and VQAHE states for in-plane (IP) magnetic anisotropy. By obtaining the real magnetic anisotropy energy (MAE) under different strains, due to spontaneous valley polarization, intrinsic out-of-plane (OOP) magnetic anisotropy, a chiral edge state, and a unit Chern number, the VQAHE can reliably appear between two HVM states. The increasing strains can induce VQAHE, which can be clarified by a band inversion between dx2-y2/dxy and dz2 orbitals, and a sign-reversible Berry curvature. Once synthesized, the Janus monolayer ScBrI would find more significant applications in topological electronic, valleytronic, and spintronic nanodevices.
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Affiliation(s)
- Kang Jia
- School of Physics and Physical Engineering, Qufu Normal University, Qufu, Shandong, 273100, People's Republic of China
| | - Xiao-Jing Dong
- School of Physics and Physical Engineering, Qufu Normal University, Qufu, Shandong, 273100, People's Republic of China
| | - Sheng-Shi Li
- School of Physics and Technology, Institute of Spintronics, University of Jinan, Jinan, Shandong, 250022, People's Republic of China.
| | - Wei-Xiao Ji
- School of Physics and Technology, Institute of Spintronics, University of Jinan, Jinan, Shandong, 250022, People's Republic of China.
| | - Chang-Wen Zhang
- School of Physics and Physical Engineering, Qufu Normal University, Qufu, Shandong, 273100, People's Republic of China
- School of Physics and Technology, Institute of Spintronics, University of Jinan, Jinan, Shandong, 250022, People's Republic of China.
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11
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Zheng H, Wu B, Wang CT, Li S, He J, Liu Z, Wang JT, Duan JA, Liu Y. Moiré Enhanced Potentials in Twisted Transition Metal Dichalcogenide Trilayers Homostructures. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023:e2207988. [PMID: 36938893 DOI: 10.1002/smll.202207988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 03/03/2023] [Indexed: 06/18/2023]
Abstract
The exploration of moiré superlatticesholds promising potential to uncover novel quantum phenomena emerging from the interplay of atomic structure and electronic correlation . However, the impact of the moiré potential modulation on the number of twisted layers has yet to be experimentally explored. Here, this work synthesizes a twisted WSe2 homotrilayer using a dry-transfer method and investigates the enhancement of the moiré potential with increasing number of twisted layers. The results of the study reveal the presence of multiple exciton resonances with positive or negative circularly polarized emission in the WSe2 homostructure with small twist angles, which are attributed to the excitonic ground and excited states confined to the moiré potential. The distinct g-factor observed in the magneto-optical spectroscopy is also shown to be a result of the confinement of the exciton in the moiré potential. The moiré potential depths of the twisted bilayer and trilayer homostructures are found to be 111 and 212 meV, respectively, an increase of 91% from the bilayer structure. These findings demonstrate that the depth of the moiré potential can be manipulated by adjusting the number of stacked layers, providing a promising avenue for exploration into highly correlated quantum phenomena.
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Affiliation(s)
- Haihong Zheng
- School of Physics and Electronics, Hunan Key Laboratory for Super-microstructure and Ultrafast Process, Central South University, 932 South Lushan Road, Changsha, Hunan, 410083, People's Republic of China
- State Key Laboratory of High-Performance Complex Manufacturing, Central South University, 932 South Lushan Road, Changsha, Hunan, 410083, People's Republic of China
| | - Biao Wu
- School of Physics and Electronics, Hunan Key Laboratory for Super-microstructure and Ultrafast Process, Central South University, 932 South Lushan Road, Changsha, Hunan, 410083, People's Republic of China
- State Key Laboratory of High-Performance Complex Manufacturing, Central South University, 932 South Lushan Road, Changsha, Hunan, 410083, People's Republic of China
| | - Chang-Tian Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Shaofei Li
- School of Physics and Electronics, Hunan Key Laboratory for Super-microstructure and Ultrafast Process, Central South University, 932 South Lushan Road, Changsha, Hunan, 410083, People's Republic of China
| | - Jun He
- School of Physics and Electronics, Hunan Key Laboratory for Super-microstructure and Ultrafast Process, Central South University, 932 South Lushan Road, Changsha, Hunan, 410083, People's Republic of China
| | - Zongwen Liu
- School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, NSW, 2006, Australia
- The University of Sydney Nano Institute, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Jian-Tao Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, People's Republic of China
| | - Ji-An Duan
- State Key Laboratory of High-Performance Complex Manufacturing, Central South University, 932 South Lushan Road, Changsha, Hunan, 410083, People's Republic of China
| | - Yanping Liu
- School of Physics and Electronics, Hunan Key Laboratory for Super-microstructure and Ultrafast Process, Central South University, 932 South Lushan Road, Changsha, Hunan, 410083, People's Republic of China
- State Key Laboratory of High-Performance Complex Manufacturing, Central South University, 932 South Lushan Road, Changsha, Hunan, 410083, People's Republic of China
- Shenzhen Research Institute of Central South University, Shenzhen, 518057, People's Republic of China
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12
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Liu F. Time- and angle-resolved photoemission spectroscopy (TR-ARPES) of TMDC monolayers and bilayers. Chem Sci 2023; 14:736-750. [PMID: 36755720 PMCID: PMC9890651 DOI: 10.1039/d2sc04124c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Accepted: 12/04/2022] [Indexed: 12/12/2022] Open
Abstract
Many unique properties in two-dimensional (2D) materials and their heterostructures rely on charge excitation, scattering, transfer, and relaxation dynamics across different points in the momentum space. Understanding these dynamics is crucial in both the fundamental study of 2D physics and their incorporation in optoelectronic and quantum devices. A direct method to probe charge carrier dynamics with momentum resolution is time- and angle-resolved photoemission spectroscopy (TR-ARPES). Such measurements have been challenging, since photoexcited carriers in many 2D monolayers reside at high crystal momenta, requiring probe photon energies in the extreme UV (EUV) regime. These challenges have been recently addressed by development of table-top pulsed EUV sources based on high harmonic generation, and the successful integration into a TR-ARPES and/or time-resolved momentum microscope. Such experiments will allow direct imaging of photoelectrons with superior time, energy, and crystal momentum resolution, with unique advantage over traditional optical measurements. Recently, TR-ARPES experiments of 2D transition metal dichalcogenide (TMDC) monolayers and bilayers have created unprecedented opportunities to reveal many intrinsic dynamics of 2D materials, such as bandgap renormalization, charge carrier scattering, relaxation, and wavefunction localization in moiré patterns. This perspective aims to give a short review of recent discoveries and discuss the challenges and opportunities of such techniques in the future.
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Affiliation(s)
- Fang Liu
- Department of Chemistry and the PULSE Institute, Stanford University Stanford California 94305 USA
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13
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Chen J, Zhou Y, Yan J, Liu J, Xu L, Wang J, Wan T, He Y, Zhang W, Chai Y. Room-temperature valley transistors for low-power neuromorphic computing. Nat Commun 2022; 13:7758. [PMID: 36522374 PMCID: PMC9755139 DOI: 10.1038/s41467-022-35396-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 11/29/2022] [Indexed: 12/23/2022] Open
Abstract
Valley pseudospin is an electronic degree of freedom that promises highly efficient information processing applications. However, valley-polarized excitons usually have short pico-second lifetimes, which limits the room-temperature applicability of valleytronic devices. Here, we demonstrate room-temperature valley transistors that operate by generating free carrier valley polarization with a long lifetime. This is achieved by electrostatic manipulation of the non-trivial band topology of the Weyl semiconductor tellurium (Te). We observe valley-polarized diffusion lengths of more than 7 μm and fabricate valley transistors with an ON/OFF ratio of 105 at room temperature. Moreover, we demonstrate an ion insertion/extraction device structure that enables 32 non-volatile memory states with high linearity and symmetry in the Te valley transistor. With ultralow power consumption (~fW valley contribution), we enable the inferring process of artificial neural networks, exhibiting potential for applications in low-power neuromorphic computing.
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Affiliation(s)
- Jiewei Chen
- grid.16890.360000 0004 1764 6123Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong, China ,grid.16890.360000 0004 1764 6123The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen, China
| | - Yue Zhou
- grid.16890.360000 0004 1764 6123Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong, China ,grid.33199.310000 0004 0368 7223Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, 430074 Wuhan, China
| | - Jianmin Yan
- grid.16890.360000 0004 1764 6123Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong, China ,grid.16890.360000 0004 1764 6123The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen, China
| | - Jidong Liu
- grid.263488.30000 0001 0472 9649International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology, Shenzhen University, 518060 Shenzhen, China
| | - Lin Xu
- grid.16890.360000 0004 1764 6123Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong, China ,grid.16890.360000 0004 1764 6123The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen, China
| | - Jingli Wang
- grid.8547.e0000 0001 0125 2443Frontier Institute of Chip and System, Fudan University, Shanghai, China
| | - Tianqing Wan
- grid.16890.360000 0004 1764 6123Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong, China
| | - Yuhui He
- grid.33199.310000 0004 0368 7223Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, 430074 Wuhan, China
| | - Wenjing Zhang
- grid.263488.30000 0001 0472 9649International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology, Shenzhen University, 518060 Shenzhen, China
| | - Yang Chai
- grid.16890.360000 0004 1764 6123Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong, China ,grid.16890.360000 0004 1764 6123The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen, China
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14
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Song F, Zu X, Zhang Z, Jia T, Wang C, Huang S, Liu Z, Xuan H, Du J. Ultrafast Drift Current Terahertz Emission Amplification in the Monolayer WSe 2/Si Heterostructure. J Phys Chem Lett 2022; 13:11398-11404. [PMID: 36458835 DOI: 10.1021/acs.jpclett.2c03347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Two-dimensional transition metal dichalcogenides (TMDs) have great potential application for seamless on-chip integration due to their strong photon-electron-spin-valley coupling. However, the contact-free measurements of the valley-coupled photocurrent in TMDs is still challenging. Here, ultrafast terahertz emission spectroscopy is employed to investigate the photocurrent dynamics in monolayer WSe2, and an interface-induced drift current amplification is found in the WSe2/Si heterostructure. The amplification of terahertz emission comes from the photocurrent enlarged by band bending in the WSe2 and Si junction, and the amplification ratio increase further near the valley resonant transition of WSe2. In addition, the valley-momentum locked photocurrent in the WSe2/Si heterostructure reserves the same chirality with monolayer WSe2 at room temperature. These findings could provide a new method for manipulating valley-momentum locked photocurrent by photon helicity and open new avenues for TMD-based valley-polarized terahertz emission devices.
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Affiliation(s)
- Fanchen Song
- State Key Laboratory of High Field Laser Physics and CAS Center for Excellence in Ultra-intense Laser Science, Shanghai Institute of Optics and Fine Mechanics (SIOM), Chinese Academy of Sciences (CAS), Shanghai201800, China
- School of Physics and Optoelectronic Engineering, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou310024, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing100049, China
| | - Xinzhi Zu
- State Key Laboratory of High Field Laser Physics and CAS Center for Excellence in Ultra-intense Laser Science, Shanghai Institute of Optics and Fine Mechanics (SIOM), Chinese Academy of Sciences (CAS), Shanghai201800, China
- School of Physics and Optoelectronic Engineering, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou310024, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing100049, China
| | - Zeyu Zhang
- School of Physics and Optoelectronic Engineering, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou310024, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing100049, China
| | - Tingyuan Jia
- State Key Laboratory of High Field Laser Physics and CAS Center for Excellence in Ultra-intense Laser Science, Shanghai Institute of Optics and Fine Mechanics (SIOM), Chinese Academy of Sciences (CAS), Shanghai201800, China
- School of Physics and Optoelectronic Engineering, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou310024, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing100049, China
| | - Chunwei Wang
- State Key Laboratory of High Field Laser Physics and CAS Center for Excellence in Ultra-intense Laser Science, Shanghai Institute of Optics and Fine Mechanics (SIOM), Chinese Academy of Sciences (CAS), Shanghai201800, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing100049, China
| | - Sihao Huang
- State Key Laboratory of High Field Laser Physics and CAS Center for Excellence in Ultra-intense Laser Science, Shanghai Institute of Optics and Fine Mechanics (SIOM), Chinese Academy of Sciences (CAS), Shanghai201800, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing100049, China
| | - Zhengzheng Liu
- State Key Laboratory of High Field Laser Physics and CAS Center for Excellence in Ultra-intense Laser Science, Shanghai Institute of Optics and Fine Mechanics (SIOM), Chinese Academy of Sciences (CAS), Shanghai201800, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing100049, China
| | - Hongwen Xuan
- GBA Branch of Aerospace Information Research Institute, Chinese Academy of Sciences, Guangzhou510700, China
| | - Juan Du
- State Key Laboratory of High Field Laser Physics and CAS Center for Excellence in Ultra-intense Laser Science, Shanghai Institute of Optics and Fine Mechanics (SIOM), Chinese Academy of Sciences (CAS), Shanghai201800, China
- School of Physics and Optoelectronic Engineering, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou310024, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing100049, China
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15
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Sheng K, Yuan HK, Zhang B. Intrinsic spin, valley and piezoelectric polarizations in room-temperature ferrovalley Janus Ti XY ( XY = SCl and SeBr) monolayers. NANOSCALE 2022; 14:15156-15164. [PMID: 36214068 DOI: 10.1039/d2nr03860a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Two-dimensional room-temperature Janus ferrovalley semiconductors with large spin, valley and piezoelectric polarizations provide fertile platforms for designing multifunctional nanodevices. Little research has been reported to date on such materials. Here, using first-principles calculations, we predict two dynamically stable Janus titanium chalcohalide (TiSCl and TiSeBr) monolayers, which are excellent piezoelectric ferrovalley semiconductors with in-plane magnetization and high magnetic transition temperatures (738 and 884 K). When an extrinsic magnetic field is used to force the magnetization along the out-of-plane direction, a large valley polarization (64 and 146 meV) can be generated in the highest valence band with a large spin-orbit coupling by the breaking of time-reversal and space-inversion symmetry, which can be further clarified by a two-band k·p model. This robust valley-contrasting physics characterized by the valley-dependent Berry curvature leads to the anomalous valley Hall effect. It can be observed by suitable hole doping or light irradiation under an in-plane electric field. Besides, we find that the missing mirror symmetry results in giant out-of-plane piezoelectric polarization (2.05 and 2.04 pm V-1). These outstanding properties give the Janus TiSCl and TiSeBr monolayers potential for a wide variety of applications in nanoelectronics, spintronics, valleytronics, piezoelectrics and other demanding areas.
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Affiliation(s)
- Kang Sheng
- School of Physical Science and Technology, Southwest University, Chongqing 400715, China.
| | - Hong-Kuan Yuan
- School of Physical Science and Technology, Southwest University, Chongqing 400715, China.
| | - Bokai Zhang
- School of Physical Science and Technology, Southwest University, Chongqing 400715, China.
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16
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Yu BW, Liu BG. Stress-driven structural and bond reconstruction in 2D ferromagnetic semiconductor VSe 2. NANOTECHNOLOGY 2022; 33:455706. [PMID: 35905699 DOI: 10.1088/1361-6528/ac8558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Accepted: 07/28/2022] [Indexed: 06/15/2023]
Abstract
Two-dimensional (2D) semiconducting transition metal dichalcogenides can be used to make high-performance electronic, spintronic, and optoelectronic devices. Recently, room-temperature ferromagnetism and semiconduction in 2D VSe2nanoflakes were attributed to the stable 2H-phase of VSe2in the 2D limit. Here, our first-principles investigation shows that a metastable semiconducting H' phase can be formed from the H VSe2 monolayer through uniaxial stress or uniaxial strain. The calculated phonon spectra indicate the dynamical stability of the metastable H' VSe2and the path of phase switching between the H and H' VSe2phases is calculated. For the uniaxial stress (or strain) scheme, the H' phase can become lower in total energy than the H phase at a transition point. The H' phase has stronger ferromagnetism and its Curier temperature can be enhanced by applying uniaxial stress or strain. Applying uniaxial stress or strain can substantially change spin-resolved electronic structures, energy band edges, and effective carrier masses for both of the H and H' phases, and can cause some flat bands near the band edges in the strained H' phase. Further analysis indicates that one of the Se-Se bonds in the H' phase can be shortened by 19% and the related Se-V-Se bond angles are reduced by 23% with respect to those of the H phase, which is believed to increase the Se-Se covalence feature and reduce the valence of the nearby V atoms. Therefore, structural and bond reconstruction can be realized by applying uniaxial stress in such 2D ferromagnetic semiconductors for potential spintronic and optoelectronic applications.
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Affiliation(s)
- Bo-Wen Yu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Bang-Gui Liu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
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17
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Chen HY, Hsu HC, Huang CC, Li MY, Li LJ, Chiu YP. Directly Visualizing Photoinduced Renormalized Momentum-Forbidden Electronic Quantum States in an Atomically Thin Semiconductor. ACS NANO 2022; 16:9660-9666. [PMID: 35584548 PMCID: PMC9245571 DOI: 10.1021/acsnano.2c02981] [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: 03/26/2022] [Accepted: 05/13/2022] [Indexed: 05/20/2023]
Abstract
Resolving the momentum degree of freedom of photoexcited charge carriers and exploring the excited-state physics in the hexagonal Brillouin zone of atomically thin semiconductors have recently attracted great interest for optoelectronic technologies. We demonstrate a combination of light-modulated scanning tunneling microscopy and the quasiparticle interference (QPI) technique to offer a directly accessible approach to reveal and quantify the unexplored momentum-forbidden electronic quantum states in transition metal dichalcogenide (TMD) monolayers. Our QPI results affirm the large spin-splitting energy at the spin-valley-coupled Q valleys in the conduction band (CB) of a tungsten disulfide monolayer. Furthermore, we also quantify the photoexcited carrier density-dependent band renormalization at the Q valleys. Our findings directly highlight the importance of the excited-state distribution at the Q valley in the band renormalization in TMDs and support the critical role of the CB Q valley in engineering the quantum electronic valley degree of freedom in TMD devices.
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Affiliation(s)
- Hao-Yu Chen
- Department
of Physics, National Taiwan University, Taipei 10617, Taiwan
| | - Hung-Chang Hsu
- Department
of Physics, National Taiwan University, Taipei 10617, Taiwan
| | - Chuan-Chun Huang
- Department
of Physics, National Taiwan University, Taipei 10617, Taiwan
| | - Ming-Yang Li
- Taiwan
Semiconductor Manufacturing Company, Hsinchu 30078, Taiwan
| | - Lain-Jong Li
- Department
of Mechanical Engineering, The University
of Hong Kong, Pokfulam Road, Hong Kong
| | - Ya-Ping Chiu
- Department
of Physics, National Taiwan University, Taipei 10617, Taiwan
- Graduate
School of Advanced Technology, National
Taiwan University, Taipei 10617, Taiwan
- Institute
of Physics, Academia Sinica, Taipei 115201, Taiwan
- Center of
Atomic Initiative for New Materials, National
Taiwan University, Taipei 10617, Taiwan
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18
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Huang L, Zhu X, Hu G, Deng C, Sun Y, Wang D, Lu M, Yun B, Zhang R, Zhang Y, Cui Y. Electrical Switching of the Off-Resonance Room-Temperature Valley Polarization in Monolayer MoS 2 by a Double-Resonance Chiral Microstructure. ACS APPLIED MATERIALS & INTERFACES 2022; 14:22381-22388. [PMID: 35511437 DOI: 10.1021/acsami.2c03688] [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
Enhancing and expanding the manipulated range of room-temperature valley polarization at off-resonance wavelength is extremely crucial to developing various functional valleytronic devices. Although these have been realized through the double-resonance strategy or twist-angle engineering, the demand for electrical control over the concepts remains elusive. Here, we fabricate a gate-tunable double-resonance chiral microstructure using a molybdenum disulfides (MoS2) monolayer. On the basis of the varied interface charge density, we demonstrate the huge photoluminescence (PL) tuning ability of this configuration. Furthermore, benefiting predominately from the screening of long-range e-h exchange interactions and the chiral Purcell effect, the electrical switching of the room-temperature valley polarization at off-resonance wavelength is also realized. Our work enriches the functions of TMDs-based optoelectronic devices and may create important applications in future valley-polarized encode and information processing devices.
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Affiliation(s)
- Lei Huang
- Advanced Photonics Center, School of Electronic Science and Engineering, Southeast University, Nanjing, Jiangsu 210096, China
| | - Xiaofan Zhu
- Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments, School of Mechanical Engineering, Southeast University, Nanjing 211189, China
| | - Guohua Hu
- Advanced Photonics Center, School of Electronic Science and Engineering, Southeast University, Nanjing, Jiangsu 210096, China
| | - Chunyu Deng
- Advanced Photonics Center, School of Electronic Science and Engineering, Southeast University, Nanjing, Jiangsu 210096, China
| | - Yu Sun
- Advanced Photonics Center, School of Electronic Science and Engineering, Southeast University, Nanjing, Jiangsu 210096, China
| | - Dongyu Wang
- Advanced Photonics Center, School of Electronic Science and Engineering, Southeast University, Nanjing, Jiangsu 210096, China
| | - Mengjia Lu
- Advanced Photonics Center, School of Electronic Science and Engineering, Southeast University, Nanjing, Jiangsu 210096, China
| | - Binfeng Yun
- Advanced Photonics Center, School of Electronic Science and Engineering, Southeast University, Nanjing, Jiangsu 210096, China
| | - Ruohu Zhang
- Advanced Photonics Center, School of Electronic Science and Engineering, Southeast University, Nanjing, Jiangsu 210096, China
| | - Yan Zhang
- Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments, School of Mechanical Engineering, Southeast University, Nanjing 211189, China
| | - Yiping Cui
- Advanced Photonics Center, School of Electronic Science and Engineering, Southeast University, Nanjing, Jiangsu 210096, China
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19
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Zhang T, Wang H, Xia X, Yan N, Sha X, Huang J, Watanabe K, Taniguchi T, Zhu M, Wang L, Gao J, Liang X, Qin C, Xiao L, Sun D, Zhang J, Han Z, Li X. A monolithically sculpted van der Waals nano-opto-electro-mechanical coupler. LIGHT, SCIENCE & APPLICATIONS 2022; 11:48. [PMID: 35232973 PMCID: PMC8888553 DOI: 10.1038/s41377-022-00734-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 01/25/2022] [Accepted: 02/08/2022] [Indexed: 06/14/2023]
Abstract
The nano-opto-electro-mechanical systems (NOEMS) are a class of hybrid solid devices that hold promises in both classical and quantum manipulations of the interplay between one or more degrees of freedom in optical, electrical and mechanical modes. To date, studies of NOEMS using van der Waals (vdW) heterostructures are very limited, although vdW materials are known for emerging phenomena such as spin, valley, and topological physics. Here, we devise a universal method to easily and robustly fabricate vdW heterostructures into an architecture that hosts opto-electro-mechanical couplings in one single device. We demonstrated several functionalities, including nano-mechanical resonator, vacuum channel diodes, and ultrafast thermo-radiator, using monolithically sculpted graphene NOEMS as a platform. Optical readout of electric and magnetic field tuning of mechanical resonance in a CrOCl/graphene vdW NOEMS is further demonstrated. Our results suggest that the introduction of the vdW heterostructure into the NOEMS family will be of particular potential for the development of novel lab-on-a-chip systems.
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Affiliation(s)
- Tongyao Zhang
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan, 030006, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, 030006, China
| | - Hanwen Wang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, China
- School of Material Science and Engineering, University of Science and Technology of China, Anhui, 230026, China
| | - Xiuxin Xia
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, China
- School of Material Science and Engineering, University of Science and Technology of China, Anhui, 230026, China
| | - Ning Yan
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan, 030006, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, 030006, China
| | - Xuanzhe Sha
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan, 030006, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, 030006, China
| | - Jinqiang Huang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, China
- School of Material Science and Engineering, University of Science and Technology of China, Anhui, 230026, China
| | - 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
| | - Mengjian Zhu
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha, 410073, China
| | - Lei Wang
- The Key Laboratory of Science and Technology on Silicon Devices, Institute of Microelectronics, Chinese Academy of Sciences, Beijing, 100029, China
| | - Jiantou Gao
- The Key Laboratory of Science and Technology on Silicon Devices, Institute of Microelectronics, Chinese Academy of Sciences, Beijing, 100029, China.
- The University of Chinese Academy of Sciences, Beijing, 100029, China.
| | - Xilong Liang
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, 030006, China
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan, 030006, China
| | - Chengbing Qin
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, 030006, China.
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan, 030006, China.
| | - Liantuan Xiao
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, 030006, China
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan, 030006, China
| | - Dongming Sun
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, China
- School of Material Science and Engineering, University of Science and Technology of China, Anhui, 230026, China
| | - Jing Zhang
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan, 030006, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, 030006, China
| | - Zheng Han
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan, 030006, China.
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, 030006, China.
| | - Xiaoxi Li
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan, 030006, China.
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, 030006, China.
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20
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Scolfaro D, Finamor M, Trinchão LO, Rosa BLT, Chaves A, Santos PV, Iikawa F, Couto ODD. Acoustically Driven Stark Effect in Transition Metal Dichalcogenide Monolayers. ACS NANO 2021; 15:15371-15380. [PMID: 34450007 DOI: 10.1021/acsnano.1c06854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The Stark effect is one of the most efficient mechanisms to manipulate many-body states in nanostructured systems. In mono- and few-layer transition metal dichalcogenides, it has been successfully induced by optical and electric field means. Here, we tune the optical emission energies and dissociate excitonic states in MoSe2 monolayers employing the 220 MHz in-plane piezoelectric field carried by surface acoustic waves. We transfer the monolayers to high dielectric constant piezoelectric substrates, where the neutral exciton binding energy is reduced, allowing us to efficiently quench (above 90%) and red-shift the excitonic optical emissions. A model for the acoustically induced Stark effect yields neutral exciton and trion in-plane polarizabilities of 530 and 630 × 10-5 meV/(kV/cm)2, respectively, which are considerably larger than those reported for monolayers encapsulated in hexagonal boron nitride. Large in-plane polarizabilities are an attractive ingredient to manipulate and modulate multiexciton interactions in two-dimensional semiconductor nanostructures for optoelectronic applications.
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Affiliation(s)
- Diego Scolfaro
- Instituto de Física "Gleb Wataghin", Universidade Estadual de Campinas, 13083-859 Campinas, Brazil
| | - Matheus Finamor
- Instituto de Física "Gleb Wataghin", Universidade Estadual de Campinas, 13083-859 Campinas, Brazil
| | - Luca O Trinchão
- Instituto de Física "Gleb Wataghin", Universidade Estadual de Campinas, 13083-859 Campinas, Brazil
| | - Bárbara L T Rosa
- Departamento de Fisica, Universidade Federal de Minas Gerais (UFMG), 30123-970 Belo Horizonte, Brazil
| | - Andrey Chaves
- Departamento de Física, Universidade Federal do Ceará, Caixa Postal 6030, Campus do Pici, 60455-900 Fortaleza, Ceará, Brazil
- Department of Physics, University of Antwerp, Groenenborgerlaan 171, B-2020, Antwerp, Belgium
| | - Paulo V Santos
- Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, 10117 Berlin, Germany
| | - Fernando Iikawa
- Instituto de Física "Gleb Wataghin", Universidade Estadual de Campinas, 13083-859 Campinas, Brazil
| | - Odilon D D Couto
- Instituto de Física "Gleb Wataghin", Universidade Estadual de Campinas, 13083-859 Campinas, Brazil
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