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Kim J, Kim Y, Sung D, Hong S. Valley-Dependent Electronic Properties of Metal Monochalcogenides GaX and Janus Ga 2XY (X, Y = S, Se, and Te). NANOMATERIALS (BASEL, SWITZERLAND) 2024; 14:1295. [PMID: 39120400 PMCID: PMC11313789 DOI: 10.3390/nano14151295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2024] [Revised: 07/10/2024] [Accepted: 07/12/2024] [Indexed: 08/10/2024]
Abstract
Two-dimensional (2D) materials have shown outstanding potential for new devices based on their interesting electrical properties beyond conventional 3D materials. In recent years, new concepts such as the valley degree of freedom have been studied to develop valleytronics in hexagonal lattice 2D materials. We investigated the valley degree of freedom of GaX and Janus GaXY (X, Y = S, Se, Te). By considering the spin-orbit coupling (SOC) effect in the band structure calculations, we identified the Rashba-type spin splitting in band structures of Janus Ga2SSe and Ga2STe. Further, we confirmed that the Zeeman-type spin splitting at the K and K' valleys of GaX and Janus Ga2XY show opposite spin contributions. We also calculated the Berry curvatures of GaX and Janus GaXY. In this study, we find that GaX and Janus Ga2XY have a similar magnitude of Berry curvatures, while having opposite signs at the K and K' points. In particular, GaTe and Ga2SeTe have relatively larger Berry curvatures of about 3.98 Å2 and 3.41 Å2, respectively, than other GaX and Janus Ga2XY.
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Affiliation(s)
| | | | | | - Suklyun Hong
- Department of Physics, Graphene Research Institute, Quantum Information Science and Technology Center, Sejong University, Seoul 05006, Republic of Korea
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2
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Bhattarai R, Minch P, Liang Y, Zhang S, Rhone TD. Strain-induced topological phase transition in ferromagnetic Janus monolayer MnSbBiS 2Te 2. Phys Chem Chem Phys 2024; 26:10111-10119. [PMID: 38483272 DOI: 10.1039/d3cp05578g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/28/2024]
Abstract
We investigate a strain-induced topological phase transition in the ferromagnetic Janus monolayer MnSbBiS2Te2 using first-principles calculations. The electronic, magnetic, and topological properties are studied under biaxial strain within the range of -8 to +8%. The ground state of monolayer MnSbBiS2Te2 is metallic with an out-of-plane magnetic easy axis. A band gap is opened when a compressive strain between -4% and -7% is applied. We observe a topological phase transition at a biaxial strain of -5%, where the material becomes a Chern insulator exhibiting a quantum anomalous hall (QAH) effect. We find that biaxial strain and spin-orbit coupling (SOC) are responsible for the topological phase transition in MnSbBiS2Te2. In addition, we find that biaxial strain can alter the direction of the magnetic easy axis of MnSbBiS2Te2. The Curie temperature is calculated using the Heisenberg model and is found to be 24 K. This study could pave the way to the design of topological materials with potential applications in spintronics, quantum computing, and dissipationless electronics.
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Affiliation(s)
- Romakanta Bhattarai
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA.
| | - Peter Minch
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA.
| | - Yunfan Liang
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA.
| | - Shengbai Zhang
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA.
| | - Trevor David Rhone
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA.
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3
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Lan M, Wang S, Liu X, Ma S, Qiao S, Li Y, Wu H, Li F, Pu Y. Large valley splitting induced by spin-orbit coupling effects in monolayer W 2NSCl. Phys Chem Chem Phys 2024; 26:8945-8951. [PMID: 38436414 DOI: 10.1039/d3cp04832b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/05/2024]
Abstract
Two-dimensional (2D) valley materials are promising materials for writing and storing information. The search for 2D materials with large valley splitting is essential for the development of spintronics and valley electronics. In this study, we theoretically design 2D W2NSCl MXenes with large valley splitting based on first-principle calculations. Due to the strong spin-orbit coupling (SOC) and the broken inversion symmetry, the W2NSCl monolayer exhibits valley splitting values of 491 meV and 83 meV at K/K' of the valence and conduction bands, respectively. The valley splitting of W2NSCl is robust to biaxial strain. Because of the broken mirror symmetry of W2NSCl, there is a Rashba effect at Γ with a Rashba parameter of 1.019 V Å. Based on the maximum localization of the Wannier function, we found the non-zero Berry curvature at K/K'. Furthermore, the non-zero Berry curvature at the K/K' valley increases monotonically with an external strain from -4% to 4%. Our finding shows that W2NSCl is a candidate material for valley electronics and spintronics applications.
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Affiliation(s)
- Mengxian Lan
- School of Science & New Energy Technology Engineering Laboratory of Jiangsu Province, Nanjing University of Posts and Telecommunications (NJUPT), Nanjing, 210046, China.
| | - Suen Wang
- School of Science & New Energy Technology Engineering Laboratory of Jiangsu Province, Nanjing University of Posts and Telecommunications (NJUPT), Nanjing, 210046, China.
| | - Xiaoyu Liu
- School of Science & New Energy Technology Engineering Laboratory of Jiangsu Province, Nanjing University of Posts and Telecommunications (NJUPT), Nanjing, 210046, China.
| | - Sai Ma
- School of Science & New Energy Technology Engineering Laboratory of Jiangsu Province, Nanjing University of Posts and Telecommunications (NJUPT), Nanjing, 210046, China.
| | - Shiqian Qiao
- School of Science & New Energy Technology Engineering Laboratory of Jiangsu Province, Nanjing University of Posts and Telecommunications (NJUPT), Nanjing, 210046, China.
| | - Ying Li
- School of Science & New Energy Technology Engineering Laboratory of Jiangsu Province, Nanjing University of Posts and Telecommunications (NJUPT), Nanjing, 210046, China.
| | - Hong Wu
- School of Science & New Energy Technology Engineering Laboratory of Jiangsu Province, Nanjing University of Posts and Telecommunications (NJUPT), Nanjing, 210046, China.
| | - Feng Li
- School of Science & New Energy Technology Engineering Laboratory of Jiangsu Province, Nanjing University of Posts and Telecommunications (NJUPT), Nanjing, 210046, China.
| | - Yong Pu
- School of Science & New Energy Technology Engineering Laboratory of Jiangsu Province, Nanjing University of Posts and Telecommunications (NJUPT), Nanjing, 210046, China.
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4
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Batista ALDO, Palheta JMT, Piotrowski MJ, Rêgo CRC, Guedes-Sobrinho D, Dias AC. Promising TMDC-like optical and excitonic properties of the TiBr 2 2H monolayer. Dalton Trans 2024; 53:746-752. [PMID: 38086661 DOI: 10.1039/d3dt03133k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
The presented simulation protocol provides a solid foundation for exploring two-dimensional materials. Taking the TiBr2 2H monolayer as an example, this material displays promising TMDC-like optical and excitonic properties, making it an excellent candidate for optoelectronic and valleytronic applications. The direct band gap semiconductor (1.19 eV) is both structurally and thermodynamically stable, with spin-orbit coupling effects revealing a broken mirror symmetry in the K and K' valleys of the band structure, as confirmed by opposite values of the Berry curvature. A direct and bright exciton ground state was found, with an exciton binding energy of 0.56 eV. The study also revealed an optical helicity selection rule, suggesting selectivity in the valley excitation by specific circular light polarizations.
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Affiliation(s)
| | - João Marcos T Palheta
- Department of Physics, Federal University of Pelotas, PO Box 354, 96010-900, Pelotas, RS, Brazil
| | - Maurício J Piotrowski
- Department of Physics, Federal University of Pelotas, PO Box 354, 96010-900, Pelotas, RS, Brazil.
| | - Celso R C Rêgo
- Institute of Nanotechnology Hermann-von-Helmholtz-Platz, Karlsruhe Institute of Technology, 76021, Karlsruhe, Germany
| | | | - Alexandre C Dias
- Institute of Physics and International Center of Physics, University of Brasília, 70919-970, Brasília, DF, Brazil.
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5
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Yin Y, Gong Q, Yi M, Guo W. Monolayer polar metals with large piezoelectricity derived from MoSi 2N 4. MATERIALS HORIZONS 2023; 10:5177-5184. [PMID: 37718912 DOI: 10.1039/d3mh00743j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/19/2023]
Abstract
The advancement of two-dimensional polar metals tends to be limited by the incompatibility between electric polarity and metallicity as well as dimension reduction. Here, we report polar and metallic Janus monolayers of the MoSi2N4 family by breaking the out-of-plane structural symmetry through Z (P/As) substitution of N. Despite the semiconducting nature of MoSi2X4 (X = N/P/As), four Janus MoSi2NxZ4-x monolayers are found to be polar metals owing to the weak coupling between the conducting electrons and electric polarity. The metallicity is originated from the Z substitution induced delocalization of occupied electrons in Mo-d orbitals. The out-of-plane electric polarizations around 1.5-15.7 pC m-1 are determined by the asymmetric out-of-plane charge distribution due to the non-centrosymmetric Janus structure. The corresponding out-of-plane piezoelectricity is further revealed as high as 18.7-73.3 pC m-1 and 0.05-0.25 pm V-1 for the piezoelectric strain and stress coefficients, respectively. The results demonstrate polar metallicity and high out-of-plane piezoelectricity in Janus MoSi2NxZ4-x monolayers and open new vistas for exploiting unusual coexisting properties in monolayers derived from the MoSi2N4 family.
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Affiliation(s)
- Yan Yin
- State Key Laboratory of Mechanics and Control for Aerospace Structures & Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education & Institute for Frontier Science & College of Aerospace Engineering, Nanjing University of Aeronautics and Astronautics (NUAA), Nanjing 210016, China.
| | - Qihua Gong
- State Key Laboratory of Mechanics and Control for Aerospace Structures & Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education & Institute for Frontier Science & College of Aerospace Engineering, Nanjing University of Aeronautics and Astronautics (NUAA), Nanjing 210016, China.
- MIIT Key Laboratory of Aerospace Information Materials and Physics & College of Physics, Nanjing University of Aeronautics and Astronautics (NUAA), Nanjing 211106, China
| | - Min Yi
- State Key Laboratory of Mechanics and Control for Aerospace Structures & Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education & Institute for Frontier Science & College of Aerospace Engineering, Nanjing University of Aeronautics and Astronautics (NUAA), Nanjing 210016, China.
| | - Wanlin Guo
- State Key Laboratory of Mechanics and Control for Aerospace Structures & Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education & Institute for Frontier Science & College of Aerospace Engineering, Nanjing University of Aeronautics and Astronautics (NUAA), Nanjing 210016, China.
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6
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Bikerouin M, Chdil O, Balli M. Solar cells based on 2D Janus group-III chalcogenide van der Waals heterostructures. NANOSCALE 2023; 15:7126-7138. [PMID: 37000599 DOI: 10.1039/d2nr06200c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Janus monolayers, realized by breaking the vertical structural symmetry of two-dimensional (2D) materials, pave the way for a new era of high-quality and high-performance atomically-thin vertical p-n heterojunction solar cells. Herein, employing first-principles computations, Janus group-III chalcogenide monolayers, MX, M2XY, MM'X2 and MM'XY (M, M' = Ga, In; X, Y = S, Se, Te), are deeply investigated in view of their implementation in 2D photovoltaic systems. Their stability analysis reveals that the 21 investigated monolayers are energetically, thermodynamically, mechanically, dynamically, and thermally stable, confirming their growth feasibility under ambient conditions. Furthermore, owing to their optimal band gap, high charge carrier mobilities, and strong light absorption, 2D Janus group-III monolayers are predicted as promising candidates for 2D excitonic solar cell applications. In fact, 46 type-II van der Waals (vdW) heterostructures with a lattice mismatch of less than 5% are identified by analyzing the band alignments of the investigated monolayers obtained through the HSE + SOC approach. In particular, 7 vertical vdW heterojunctions with a power conversion efficiency (PCE) higher than 20% are predicted and might be the focus of future experimental and theoretical studies. To further confirm the type II band alignment, the Ga2STe-GaInS2 vdW heterostructure, which reveals the highest PCE of 23.69%, is thoroughly investigated. Our results not only predict and evaluate stable 2D Janus group-III chalcogenide monolayers and vdW heterostructures, but also suggest that they could be used as materials for next-generation optoelectronic and photovoltaic devices.
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Affiliation(s)
- M Bikerouin
- AMEEC team, LERMA, College of Engineering and Architecture, International University of Rabat, parc Technopolis, Rocade de Rabat-Salé, 11100, Morocco.
| | - O Chdil
- AMEEC team, LERMA, College of Engineering and Architecture, International University of Rabat, parc Technopolis, Rocade de Rabat-Salé, 11100, Morocco.
| | - M Balli
- AMEEC team, LERMA, College of Engineering and Architecture, International University of Rabat, parc Technopolis, Rocade de Rabat-Salé, 11100, Morocco.
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7
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Li X, Zhang F, Li J, Wang Z, Huang Z, Yu J, Zheng K, Chen X. Pentagonal C mX nY 6-m-n ( m = 2, 3; n = 1, 2; X, Y = B, N, Al, Si, P) Monolayers: Janus Ternaries Combine Omnidirectional Negative Poisson Ratios with Giant Piezoelectric Effects. J Phys Chem Lett 2023; 14:2692-2701. [PMID: 36892273 DOI: 10.1021/acs.jpclett.3c00058] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Two-dimensional (2D) materials composed of pentagon and Janus motifs usually exhibit unique mechanical and electronic properties. In this work, a class of ternary carbon-based 2D materials, CmXnY6-m-n (m = 2, 3; n = 1, 2; X, Y = B, N, Al, Si, P), are systematically studied by first-principles calculations. Six of 21 Janus penta-CmXnY6-m-n monolayers are dynamically and thermally stable. The Janus penta-C2B2Al2 and Janus penta-Si2C2N2 exhibit auxeticity. More strikingly, Janus penta-Si2C2N2 exhibits an omnidirectional negative Poisson ratio (NPR) with values ranging from -0.13 to -0.15; in other words, it is auxetic under stretch in any direction. The calculations of piezoelectricity reveal that the out-of-plane piezoelectric strain coefficient (d32) of Janus panta-C2B2Al2 is up to 0.63 pm/V and increases to 1 pm/V after a strain engineering. These omnidirectional NPR, giant piezoelectric coefficients endow the Janus pentagonal ternary carbon-based monolayers as potential candidates in the future nanoelectronics, especially in the electromechanical devices.
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Affiliation(s)
- Xiaowen Li
- College of Optoelectronic Engineering and Key Laboratory of Optoelectronic Technology & Systems Education Ministry of China, Chongqing University, 400044 Chongqing, China
| | - Fusheng Zhang
- School of Electrical Engineering and State Key Laboratory of Power Transmission Equipment & System Security and New Technology, Chongqing University, 400044 Chongqing, China
| | - Jian Li
- School of Electrical Engineering and State Key Laboratory of Power Transmission Equipment & System Security and New Technology, Chongqing University, 400044 Chongqing, China
| | - Zeping Wang
- College of Optoelectronic Engineering and Key Laboratory of Optoelectronic Technology & Systems Education Ministry of China, Chongqing University, 400044 Chongqing, China
| | - Zhengyong Huang
- School of Electrical Engineering and State Key Laboratory of Power Transmission Equipment & System Security and New Technology, Chongqing University, 400044 Chongqing, China
| | - Jiabing Yu
- College of Optoelectronic Engineering and Key Laboratory of Optoelectronic Technology & Systems Education Ministry of China, Chongqing University, 400044 Chongqing, China
| | - Kai Zheng
- College of Optoelectronic Engineering and Key Laboratory of Optoelectronic Technology & Systems Education Ministry of China, Chongqing University, 400044 Chongqing, China
- Department of Energy Conversion and Storage, Technical University of Denmark, Kongens, Lyngby 2800, Denmark
| | - Xianping Chen
- College of Optoelectronic Engineering and Key Laboratory of Optoelectronic Technology & Systems Education Ministry of China, Chongqing University, 400044 Chongqing, China
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8
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Cheng K, Hu W, Guo X, Wu L, Guo S, Su Y. Electronic structures and photovoltaic applications of vdW heterostructures based on Janus group-IV monochalcogenides: insights from first-principles calculations. Phys Chem Chem Phys 2023; 25:5663-5672. [PMID: 36734472 DOI: 10.1039/d2cp05663a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The van der Waals integration can help 2D materials modulate their properties and provide more opportunities for 2D materials in the next-generation high-performance optoelectronic devices. Using first-principles calculations, we explored the atomic and electronic structures of 2D pristine and Janus group-IV monochalcogenides and found the internal vertical electric field at Janus group-IV monochalcogenides. Then, we constructed vdW heterostructures with pristine and Janus group-IV monochalcogenides monolayers as building blocks and explored their atomic structures and band alignments. Our results demonstrate that these vdW heterostructures can be synthesized experimentally, and the surface termination of the Janus monolayer at the interface can significantly help the heterostructure realize the transition from type I to type II due to the intrinsic electric field. Moreover, we found eight vdW heterostructures with a mismatch of less than 5% exhibiting type II band alignment with charge densities of VBM and CBM mainly localized at different domains of heterostructures, and excellent power conversion efficiency (∼19%) in photovoltaics are also predicted for these heterostructures with type II band alignment. Our results not only give an idea to use the Janus monolayer as building blocks to construct vdW heterostructures and modulate their band alignment but also provide a guide to the experimental researcher to design more efficient photovoltaic devices with Janus group-IV monochalcogenides.
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Affiliation(s)
- Kai Cheng
- School of Electronic Engineering, Xi'an University of Posts and Telecommunications, Xi'an 710121, China.
| | - Wenbo Hu
- School of Electronic Engineering, Xi'an University of Posts and Telecommunications, Xi'an 710121, China.
| | - Xu Guo
- School of Electronic Engineering, Xi'an University of Posts and Telecommunications, Xi'an 710121, China.
| | - Lifan Wu
- School of Electronic Engineering, Xi'an University of Posts and Telecommunications, Xi'an 710121, China.
| | - Sandong Guo
- School of Electronic Engineering, Xi'an University of Posts and Telecommunications, Xi'an 710121, China.
| | - Yan Su
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024, China.
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9
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Yang Q, Zhang T, Hu CE, Chen XR, Geng HY. A first-principles study on the electronic, piezoelectric, and optical properties and strain-dependent carrier mobility of Janus TiXY (X ≠ Y, X/Y = Cl, Br, I) monolayers. Phys Chem Chem Phys 2022; 25:274-285. [PMID: 36475497 DOI: 10.1039/d2cp03973g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Janus transition metal dichalcogenide monolayers (TMDs) have attracted wide attention due to their unique physical and chemical properties since the successful synthesis of the MoSSe monolayer. However, the related studies of Janus monolayers of transition metal halides (TMHs) with similar structures have rarely been reported. In this article, we systematically investigate the electronic properties, piezoelectric properties, optical properties, and carrier mobility of new Janus TiXY (X ≠ Y, X/Y = Cl, Br, I) monolayers using first principles calculations for the first time. These Janus TiXY monolayers are thermally, dynamically, and mechanically stable, and their energy bands near the Fermi level (EF) are almost entirely contributed by the central Ti atom. Besides, the Janus TiXY monolayers exhibit excellent in-plane and out-of-plane piezoelectric effects, especially with an in-plane piezoelectric coefficient of ∼4.58 pm V-1 for the TiBrI monolayer and an out-of-plane piezoelectric coefficient of ∼1.63 pm V-1 for the TiClI monolayer, suggesting their promising applications in piezoelectric sensors and energy storage applications. The absorption spectra of Janus TiXY monolayers are mainly distributed in the visible and infrared regions, implying that they are fantastic candidates for photoelectric and photovoltaic applications. The obtained carrier mobilities revealed that TiXY monolayers are hole-type semiconductors. Under uniaxial compressive strain, the hole mobilities of these monolayers are gradually improved, indicating that TiXY monolayers have potential applications in the field of flexible electronic devices.
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Affiliation(s)
- Qiu Yang
- Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China.
| | - Tian Zhang
- College of Physics and Electronic Engineering, Sichuan Normal University, Chengdu 610066, China
| | - Cui-E Hu
- College of Physics and Electronic Engineering, Chongqing Normal University, Chongqing 400047, China.
| | - Xiang-Rong Chen
- Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China.
| | - Hua-Yun Geng
- National Key Laboratory for Shock Wave and Detonation Physics Research, Institute of Fluid Physics, CAEP, Mianyang 621900, China
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10
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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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11
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Lu J, Qu F, Zeng H, Cavalheiro Dias A, Bradão DS, Ren J. Intrinsic Valley Splitting and Direct-to-Indirect Band Gap Transition in Monolayer HfZrSiCO 2. J Phys Chem Lett 2022; 13:5204-5212. [PMID: 35666623 DOI: 10.1021/acs.jpclett.2c01090] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Both a reasonably large valley splitting (VS) and a sufficiently long valley exciton lifetime are crucial in valleytronics device applications. Currently, no single system possesses both attributes simultaneously. Herein, we demonstrate that a Janus monolayer HfZrSiCO2 concurrently hosts a giant intrinsic VS and excitonic quasi-particles with long valley lifetime due to valley-sublayer coupling and built-in electric field. In addition, the band structure of the monolayer HfZrSiCO2 can be continuously manipulated by either an external electric field or a biaxial strain, giving rise to a tunable VS and driving a direct-to-indirect band gap transition. Moreover, the system exhibits valley-contrasting linear dichroism in exciton absorption. These results suggest that the Janus monolayer HfZrSiCO2 is a promising candidate for information applications.
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Affiliation(s)
- Jiajun Lu
- School of Physics and Electronics, Shandong Normal University, Jinan 250014, China
| | - Fanyao Qu
- Instituto de Física, Universidade de Brasília, Brasília-DF 70919-970, Brazil
- International Center for Condensed Matter Physics, University of Brasília, 04513 Brasília-DF, Brazil
| | - Hao Zeng
- Department of Physics, University at Buffalo, the State University of New York, Buffalo, New York 14260, United States
| | - Alexandre Cavalheiro Dias
- Instituto de Física, Universidade de Brasília, Brasília-DF 70919-970, Brazil
- International Center for Condensed Matter Physics, University of Brasília, 04513 Brasília-DF, Brazil
| | - David S Bradão
- Instituto de Física, Universidade de Brasília, Brasília-DF 70919-970, Brazil
| | - Junfeng Ren
- School of Physics and Electronics, Shandong Normal University, Jinan 250014, China
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12
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Abstract
Layered van der Waals (vdW) materials have attracted significant attention due to their materials properties that can enhance diverse applications including next-generation computing, biomedical devices, and energy conversion and storage technologies. This class of materials is typically studied in the two-dimensional (2D) limit by growing them directly on bulk substrates or exfoliating them from parent layered crystals to obtain single or few layers that preserve the original bonding. However, these vdW materials can also function as a platform for obtaining additional phases of matter at the nanoscale. Here, we introduce and review a synthesis paradigm, morphotaxy, where low-dimensional materials are realized by using the shape of an initial nanoscale precursor to template growth or chemical conversion. Using morphotaxy, diverse non-vdW materials such as HfO2 or InF3 can be synthesized in ultrathin form by changing the composition but preserving the shape of the original 2D layered material. Morphotaxy can also enable diverse atomically precise heterojunctions and other exotic structures such as Janus materials. Using this morphotaxial approach, the family of low-dimensional materials can be substantially expanded, thus creating vast possibilities for future fundamental studies and applied technologies.
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Affiliation(s)
- David Lam
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Dmitry Lebedev
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Mark C Hersam
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
- Department of Electrical and Computer Engineering, Northwestern University, Evanston, Illinois 60208, United States
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13
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Wang L, Lin Z, Du Y, Qiu J, Chen X, Yu J. The piezoelectricity of 2D Janus ZnBrI: Multiscale prediction. Chem Phys Lett 2022. [DOI: 10.1016/j.cplett.2022.139506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Nayak D, Thangavel R. A density functional theory study on the strain modulated electronic and photocatalytic properties of a GaSe monolayer for photocatalytic water splitting and artificial photosynthesis. NEW J CHEM 2022. [DOI: 10.1039/d2nj00956k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The strain modulated electronic and photocatalytic properties of GaSe monolayer for photocatalytic water splitting and artificial photosynthesis using DFT study.
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Affiliation(s)
- Dipali Nayak
- Condensed Matter Physics Laboratory, Department of Physics, Indian Institute of Technology (Indian School of Mines), Dhanbad-826004, Jharkhand, India
| | - R. Thangavel
- Condensed Matter Physics Laboratory, Department of Physics, Indian Institute of Technology (Indian School of Mines), Dhanbad-826004, Jharkhand, India
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15
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Dat VD, Vu TV. Janus monolayer HfSO with improved optical properties as a novel material for photovoltaic and photocatalyst applications. NEW J CHEM 2022. [DOI: 10.1039/d1nj05096f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
First principles calculations were performed to investigate the photocatalytic behavior of 2D Janus monolayer HfSO at equilibrium and under the influence of strains and external electric fields.
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Affiliation(s)
- Vo D. Dat
- Group of Computational Physics and Simulation of Advanced Materials, Institute of Applied Technology, Thu Dau Mot University, Binh Duong Province, Vietnam
| | - Tuan V. Vu
- Division of Computational Physics, Institute for Computational Science, Ton Duc Thang University, Ho Chi Minh City, Vietnam
- Faculty of Electrical & Electronics Engineering, Ton Duc Thang University, Ho Chi Minh City, Vietnam
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16
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Guo J, Lu Z, Wang K, Zhao X, Hu G, Yuan X, Ren J. Large valley polarization in a novel two-dimensional semiconductor H-ZrX 2(X =Cl, Br, I). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 34:075701. [PMID: 34768243 DOI: 10.1088/1361-648x/ac394f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 11/12/2021] [Indexed: 06/13/2023]
Abstract
Inspired by the new progress in the research field of two-dimensional valleytronics materials, we propose a new class of transition metal halides, i.e. H-ZrX2(X = Cl, Br, I), and investigated their valleytronics properties under the first-principles calculations. It harbors the spin-valley coupling at K and K' points in the top of valence band, in which the valley spin splitting of ZrI2can reach up to 115 meV. By carrying out the strain engineering, the valley spin splitting and Berry curvature can be effectively tuned. The long-sought valley polarization reaches up to 108 meV by doping Cr atom, which corresponds to the large Zeeman magnetic field of 778 T. Furthermore, the valley polarization in ZrX2can be lineally adjusted or flipped by manipulating the magnetization orientation of the doped magnetic atoms. All the results demonstrate the well-founded application prospects of single-layer ZrX2, which can be considered as great candidate for the development of valleytronics and spintronics.
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Affiliation(s)
- Jiatian Guo
- School of Physics and Electronics, Shandong Normal University, Jinan 250014, People's Republic of China
| | - Zhutong Lu
- School of Physics and Electronics, Shandong Normal University, Jinan 250014, People's Republic of China
| | - Keyu Wang
- School of Physics and Electronics, Shandong Normal University, Jinan 250014, People's Republic of China
| | - Xiuwen Zhao
- School of Physics and Electronics, Shandong Normal University, Jinan 250014, People's Republic of China
| | - Guichao Hu
- School of Physics and Electronics, Shandong Normal University, Jinan 250014, People's Republic of China
| | - Xiaobo Yuan
- School of Physics and Electronics, Shandong Normal University, Jinan 250014, People's Republic of China
| | - Junfeng Ren
- School of Physics and Electronics, Shandong Normal University, Jinan 250014, People's Republic of China
- Shandong Provincial Engineering and Technical Center of Light Manipulations & Institute of Materials and Clean Energy, Shandong Normal University, Jinan 250014, People's Republic of China
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17
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Zhang L, Gu Y, Du A. Two-Dimensional Janus Antimony Selenium Telluride with Large Rashba Spin Splitting and High Electron Mobility. ACS OMEGA 2021; 6:31919-31925. [PMID: 34870014 PMCID: PMC8638011 DOI: 10.1021/acsomega.1c04680] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 11/05/2021] [Indexed: 06/13/2023]
Abstract
Janus two-dimensional materials with large Rashba spin splitting and high electron mobility are rarely reported but highly desired for nanoscale spintronics. Herein, using density functional theory calculations, we predicated Janus Sb2Se x Te3-x (x = 1 or 2) monolayers simultaneously harboring these fascinating properties. The predicated monolayers are indirect semiconductors with great dynamical, thermal, and mechanical stability. The spin-orbital coupling (SOC) and the out-of-plane asymmetry lead to Rashba spin splitting at the conduction band minimum (CBM), which can be effectively tuned by the small uniaxial strain. The strong band dispersion at the CBM leads to small electron effective mass, consequently enabling a high electron mobility that reaches up to 6816.63 cm2 V-1 s-1. Moreover, Janus Sb2Se x Te3-x monolayers possess great light absorption capability within the visible and infrared regions of solar light. Our findings highlight promising candidates for high-speed spintronic devices and may motivate more research efforts on carrier transport and SOC effects in Janus group V and VI monolayers.
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Affiliation(s)
- Lei Zhang
- School
of Chemistry and Physics, Queensland University
of Technology, Gardens Point
Campus, Brisbane, QLD 4000, Australia
- Centre
for Materials Science, Queensland University
of Technology, Gardens Point
Campus, Brisbane, QLD 4000, Australia
| | - Yuantong Gu
- School
of Mechanical, Medical and Process Engineering, Queensland University of Technology, Gardens Point Campus, Brisbane, QLD 4000, Australia
| | - Aijun Du
- School
of Chemistry and Physics, Queensland University
of Technology, Gardens Point
Campus, Brisbane, QLD 4000, Australia
- Centre
for Materials Science, Queensland University
of Technology, Gardens Point
Campus, Brisbane, QLD 4000, Australia
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18
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Zhao ZY, Liu QL. Rational Design of a Two-Dimensional Janus CuFeO 2+δ Single Layer as a Photocatalyst and Photoelectrode. J Phys Chem Lett 2021; 12:10863-10873. [PMID: 34730358 DOI: 10.1021/acs.jpclett.1c02627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The exfoliation of 2D nanomaterials from 3D multimetal oxides with a stable structure is a great challenge. Herein, a delafossite CuFeO2+δ nanosheet becomes an open-layered structure by introducing excess oxygen so that the 2D Janus CuFeO2+δ single layer can be further obtained by aqueous ultrasonic exfoliation. The 2D Janus CuFeO2+δ single layer breaks the limitation of mirror symmetry, which is very beneficial to the effective separation of photogenerated electron-hole pairs. Serving as both a photoelectrode and a photocatalyst, the 2D Janus CuFeO2+δ single layer/few layer remarkably enhances the photocatalytic activity with long-term stability: the photocurrent density is increased by 2-fold, and the rate of H2 evolution is increased by 1.5-fold, in comparison with the counterpart of unexfoliated CuFeO2+δ nanosheets. This work demonstrates that 2D nanomaterials can be directly exfoliated from 3D nanomaterials by rational composition and microstructure design, which is helpful in promoting the development of bimetallic-oxide-ene (BMOene) as a novel functional material.
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Affiliation(s)
- Zong-Yan Zhao
- Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093, People's Republic of China
| | - Qing-Lu Liu
- Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093, People's Republic of China
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19
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Li R, Jiang J, Mi W, Bai H. Room temperature spontaneous valley polarization in two-dimensional FeClBr monolayer. NANOSCALE 2021; 13:14807-14813. [PMID: 34533179 DOI: 10.1039/d1nr04063d] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The valley degrees of freedom of Bloch electrons provide a proper platform to realize information storage and processing. Using first principles calculations, we propose that the FeClBr monolayer is a ferromagnetic semiconductor with spontaneous valley polarization owing to the combined effect of magnetic exchange interaction and spin-orbit coupling effect. The FeClBr monolayer shows perpendicular magnetic anisotropy, a high Curie temperature of 651 K and a large valley splitting of 188 meV, which are beneficial for the practical applications in valleytronics. Then, the anomalous valley Hall effect can be realized under an in-plane electrical field due to the valley-contrasting berry curvature. According to the optical selectivity rule, the different valleys at K and K- points in momentum space can be excited by the circularly polarized light in honeycomb structures; however, the FeClBr monolayer can also respond to the linear light. Therefore, the valley degree of freedom of the FeClBr monolayer can be modulated by circularly polarized light, linear light and hole doping. Our work enriches the library of valley materials and provides a candidate for the study of spintronics and valleytronics field.
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Affiliation(s)
- Rui Li
- Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparation Technology, School of Science, Tianjin University, Tianjin 300354, China.
| | - Jiawei Jiang
- Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparation Technology, School of Science, Tianjin University, Tianjin 300354, China.
| | - Wenbo Mi
- Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparation Technology, School of Science, Tianjin University, Tianjin 300354, China.
| | - Haili Bai
- Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparation Technology, School of Science, Tianjin University, Tianjin 300354, China.
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20
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Chen S, Sun H, Ding J, Wu F, Huang C, Kan E. Unconventional distortion induced two-dimensional multiferroicity in a CrO 3 monolayer. NANOSCALE 2021; 13:13048-13056. [PMID: 34477788 DOI: 10.1039/d1nr02335g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Two-dimensional (2D) multiferroic materials with the coexistence of electric and spin polarization offer a tantalizing potential for high-density multistate data storage. However, intrinsic 2D multiferroic semiconductors with high thermal stability are still rare to date. Here, we propose a new mechanism of single-phase multiferroicity. Based on first-principles calculations, we predicted that in a CrO3 monolayer, the unconventional distortion of the square antiprismatic crystal field on Cr-d orbitals will induce an in-plane electric polarization, making this material a single-phase multiferroic semiconductor. Importantly, the magnetic Curie temperature is estimated to be ∼220 K, which is quite high as compared to those of the recently reported 2D ferromagnetic and multiferroic semiconductors. Moreover, both ferroelectric and antiferroelectric phases are observed, providing opportunities for electrical control of magnetism and energy storage and conversion applications. These findings provide a comprehensive understanding of the magnetic and electric behavior in 2D multiferroics and will motivate further research on the application of related 2D electromagnetics and spintronics.
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Affiliation(s)
- Shanbao Chen
- MIIT Key Laboratory of Semiconductor Microstructure and Quantum Sensing and Department of Applied Physics, Nanjing University of Science and Technology, Nanjing 210094, P. R. China.
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21
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Zhang S, Wang Y, Wang S, Huang B, Dai Y, Wei W. Electronic Properties of Monolayer and van der Waals Bilayer of Janus TiClI. J Phys Chem Lett 2021; 12:2245-2251. [PMID: 33635653 DOI: 10.1021/acs.jpclett.1c00149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
In this work, the novel electronic properties of the Janus TiClI monolayer (ML) and van der Waals (vdW) bilayers (BLs) have been demonstrated. As a result of the strong spin-orbit coupling (SOC) together with the inversion symmetry breaking, the TiClI ML shows valley spin splitting of 62.67 meV at the K/K' point. In magnetic V- and Cr-doped TiClI MLs, sizable valley polarization of 36.70 and 45.35 meV occurs, respectively. TiClI vdW BLs indicate typical type-II band alignment with a quite large band offset (>500 meV), and interestingly, the interlayer-polarization PH is almost 100% for all considered stacking orders. In addition, the interlayer-polarization is insensitive to the interlayer distance. In this situation, the interlayer exciton and valley polarization lifetimes could be prolonged, and thus, TiClI vdW BLs provide new opportunities for light-energy conversion and valleytronics. As the interlayer distance decreases, the TiClI BLs of AB' and AB stacking indicate a semiconductor-to-metal transition and are characterized by hole-doping, and the doping concentration can be further tuned by changing the interlayer distance.
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Affiliation(s)
- Shuhui Zhang
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
| | - Yuanyuan Wang
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
| | - Shuhua Wang
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
| | - Baibiao Huang
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
| | - Ying Dai
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
| | - Wei Wei
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
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22
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Van On V, Nguyen DK, Guerrero-Sanchez J, Hoat DM. Exploring the electronic band gap of Janus MoSeO and WSeO monolayers and their heterostructures. NEW J CHEM 2021. [DOI: 10.1039/d1nj04427c] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Electronic band structure of TMSeO monolayers.
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Affiliation(s)
- Vo Van On
- Group of Computational Physics and Simulation of Advanced Materials, Institute of Applied Technology, Thu Dau Mot University, Binh Duong Province, Vietnam
| | - Duy Khanh Nguyen
- Group of Computational Physics and Simulation of Advanced Materials, Institute of Applied Technology, Thu Dau Mot University, Binh Duong Province, Vietnam
| | - J. Guerrero-Sanchez
- Universidad Nacional Autónoma de México, Centro de Nanociencias y Nanotecnología, Apartado Postal 14, Ensenada, Baja California, Código Postal 22800, Mexico
| | - D. M. Hoat
- Institute of Theoretical and Applied Research, Duy Tan University, Ha Noi 100000, Vietnam
- Faculty of Natural Sciences, Duy Tan University, Da Nang 550000, Vietnam
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23
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Cheng Z, Sun J, Zhang B, Lu Z, Ma F, Zhang G, Xue Q. Strain Effects of Vertical Separation and Horizontal Sliding in Commensurate Two-Dimensional Homojunctions. J Phys Chem Lett 2020; 11:5815-5822. [PMID: 32614591 DOI: 10.1021/acs.jpclett.0c01713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Strain, as an economic yet controllable approach for structural modulation, frequently plays a vital role in the preparation and performance optimization of two-dimensional nanomaterials (TNMs). Here, utilizing first-principles simulations, the analysis of energetics shows that the biaxial stretching and compressing could facilitate the vertical separation and horizontal sliding in graphene (Gr/Gr), hexagonal boron nitride (h-BN/h-BN), and molybdenum disulfide (MoS2/MoS2) bilayers. The quantification of electron redistribution between layers confirmed that the shifts of interlayer charge density (ρinter-) and its relative values (Δρinter-) are responsible for the vertical separation and horizontal sliding facilitated by biaxial strain. More effortless horizontal sliding was enabled by a smoother potential energy surface because a smaller Δρinter- can be acquired under compression, whereas more effortless vertical separation followed a more vulnerable surface energy because a lower ρinter- occurs under tensile strain. The vertical and horizontal division of strain effect provides a novel idea for further understanding its pivotal roles in strain engineering of commensurate-contact TNMs, such as mechanical exfoliation and solid lubrication.
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Affiliation(s)
- Ziwen Cheng
- Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
- Institute of Nanoscience and Nanotechnology, School of Physical Science and Technology, Lanzhou University, Lanzhou 730000, China
| | - Junhui Sun
- Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China
- School of Mechanical Engineering, State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031, China
| | - Bozhao Zhang
- Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Zhibin Lu
- Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Fei Ma
- Institute of Nanoscience and Nanotechnology, School of Physical Science and Technology, Lanzhou University, Lanzhou 730000, China
| | - Guangan Zhang
- Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qunji Xue
- Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China
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Zhou B. Ferroelectric Rashba semiconductors, AgBiP 2X 6 (X = S, Se and Te), with valley polarization: an avenue towards electric and nonvolatile control of spintronic devices. NANOSCALE 2020; 12:5533-5542. [PMID: 32091050 DOI: 10.1039/c9nr10865c] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The electric and nonvolatile control of spin in semiconductors represents a fundamental step towards novel electronic devices. In this work, using first-principles calculations we investigate the electronic properties of AgBiP2X6 (X = S, Se, and Te) monolayers, which may be a new member of ferroelectric Rashba semiconductors due to the inversion symmetry breaking arising from the ferroelectric polarization, thus allowing for the electric control of spin. The AgBiP2X6 monolayers are dynamically and thermodynamically stable up to room temperature. In the AgBiP2Te6 monolayer, the calculated band structure reveals the direct band-gap semiconducting nature in the presence of highly mobile two-dimensional electron gas near the Fermi level. The inclusion of spin-orbit coupling yields the giant Rashba-type spin splitting with a Rashba parameter of 6.5 eV Å, which is even comparable to that of some known bulk Rashba semiconductors. Except for the Rashba-type spin splitting, spin-orbit coupling together with inversion symmetry breaking also gives rise to valley polarization located at the edge of the conduction bands. The strength of the Rashba-type spin splitting and location of the conduction band minimum can be significantly tuned by applying the in-plane biaxial strain. Also, we demonstrate that these remarkable features can be retained in the presence of the BN substrate. The coexistence of the Rashba-type spin splitting (in-plane spin direction) and band splitting at the K/K' valleys (out-of-plane spin direction) makes the AgBiP2Te6 monolayer interesting for spintronics and valleytronics.
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Affiliation(s)
- Baozeng Zhou
- Tianjin Key Laboratory of Film Electronic & Communicate Devices, School of Electrical and Electronic Engineering, Tianjin University of Technology, Tianjin 300384, China.
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