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Jiang Y, Sun H, Guo J, Liang Y, Qin P, Yang Y, Luo L, Leng L, Gong X, Wu Z. Vacancy Engineering in 2D Transition Metal Chalcogenide Photocatalyst: Structure Modulation, Function and Synergy Application. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2310396. [PMID: 38607299 DOI: 10.1002/smll.202310396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 03/08/2024] [Indexed: 04/13/2024]
Abstract
Transition metal chalcogenides (TMCs) are widely used in photocatalytic fields such as hydrogen evolution, nitrogen fixation, and pollutant degradation due to their suitable bandgaps, tunable electronic and optical properties, and strong reducing ability. The unique 2D malleability structure provides a pre-designed platform for customizable structures. The introduction of vacancy engineering makes up for the shortcomings of photocorrosion and limited light response and provides the greatest support for TMCs in terms of kinetics and thermodynamics in photocatalysis. This work reviews the effect of vacancy engineering on photocatalytic performance based on 2D semiconductor TMCs. The characteristics of vacancy introduction strategies are summarized, and the development of photocatalysis of vacancy engineering TMCs materials in energy conversion, degradation, and biological applications is reviewed. The contribution of vacancies in the optical range and charge transfer kinetics is also discussed from the perspective of structure manipulation. Vacancy engineering not only controls and optimizes the structure of the TMCs, but also improves the optical properties, charge transfer, and surface properties. The synergies between TMCs vacancy engineering and atomic doping, other vacancies, and heterojunction composite techniques are discussed in detail, followed by a summary of current trends and potential for expansion.
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Affiliation(s)
- Yi Jiang
- Key Laboratory for Rural Ecosystem Health in the Dongting Lake Area of Hunan Province, College of Environment and Ecology, Hunan Agricultural University, Changsha, 410128, P. R. China
| | - Haibo Sun
- Key Laboratory for Rural Ecosystem Health in the Dongting Lake Area of Hunan Province, College of Environment and Ecology, Hunan Agricultural University, Changsha, 410128, P. R. China
| | - Jiayin Guo
- School of Resources and Environment, Hunan University of Technology and Business, Changsha, 410205, P. R. China
| | - Yunshan Liang
- Key Laboratory for Rural Ecosystem Health in the Dongting Lake Area of Hunan Province, College of Environment and Ecology, Hunan Agricultural University, Changsha, 410128, P. R. China
| | - Pufeng Qin
- Key Laboratory for Rural Ecosystem Health in the Dongting Lake Area of Hunan Province, College of Environment and Ecology, Hunan Agricultural University, Changsha, 410128, P. R. China
| | - Yuan Yang
- Key Laboratory for Rural Ecosystem Health in the Dongting Lake Area of Hunan Province, College of Environment and Ecology, Hunan Agricultural University, Changsha, 410128, P. R. China
| | - Lin Luo
- Key Laboratory for Rural Ecosystem Health in the Dongting Lake Area of Hunan Province, College of Environment and Ecology, Hunan Agricultural University, Changsha, 410128, P. R. China
| | - Lijian Leng
- School of Energy Science and Engineering, Central South University, Changsha, 410083, P. R. China
| | - Xiaomin Gong
- Key Laboratory for Rural Ecosystem Health in the Dongting Lake Area of Hunan Province, College of Environment and Ecology, Hunan Agricultural University, Changsha, 410128, P. R. China
| | - Zhibin Wu
- Key Laboratory for Rural Ecosystem Health in the Dongting Lake Area of Hunan Province, College of Environment and Ecology, Hunan Agricultural University, Changsha, 410128, P. R. China
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2
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Xu J, Ping Y. Ab Initio Predictions of Spin Relaxation, Dephasing, and Diffusion in Solids. J Chem Theory Comput 2024; 20:492-512. [PMID: 38157422 DOI: 10.1021/acs.jctc.3c00598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
Spin relaxation, dephasing, and diffusion are at the heart of spin-based information technology. Accurate theoretical approaches to simulate spin lifetimes (τs), determining how fast the spin polarization and phase information will be lost, are important to the understanding of the underlying mechanism of these spin processes, and invaluable in searching for promising candidates of spintronic materials. Recently, we develop a first-principles real-time density-matrix (FPDM) approach to simulate spin dynamics for general solid-state systems. Through the complete first-principles descriptions of light-matter interaction and scattering processes including electron-phonon, electron-impurity, and electron-electron scatterings with self-consistent spin-orbit coupling, as well as ab initio Landé g-factor, our method can predict τs at various conditions as a function of carrier density and temperature, under electric and magnetic fields. By employing this method, we successfully reproduce experimental results of disparate materials and identify the key factors affecting spin relaxation, dephasing, and diffusion in different materials. Specifically, we predict that germanene has long τs (∼100 ns at 50 K), a giant spin lifetime anisotropy, and spin-valley locking effect under electric fields, making it advantageous for spin-valleytronic applications. Based on our theoretical derivations and ab initio simulations, we propose a new useful electronic quantity, named spin-flip angle θ↑↓, for the understanding of spin relaxation through intervalley spin-flip scattering processes. Our method can be further applied to other emerging materials and extended to simulate exciton spin dynamics and steady-state photocurrents due to photogalvanic effect.
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Affiliation(s)
- Junqing Xu
- Department of Physics, Hefei University of Technology, Hefei 230031, Anhui China
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, United States
| | - Yuan Ping
- Department of Materials Science and Engineering, University of Wisconsin─Madison, Madison, Wisconsin 53706, United States
- Department of Physics, University of California, Santa Cruz, California 95064, United States
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3
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Xu J, Li K, Huynh UN, Fadel M, Huang J, Sundararaman R, Vardeny V, Ping Y. How spin relaxes and dephases in bulk halide perovskites. Nat Commun 2024; 15:188. [PMID: 38168025 PMCID: PMC10761878 DOI: 10.1038/s41467-023-42835-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 10/23/2023] [Indexed: 01/05/2024] Open
Abstract
Spintronics in halide perovskites has drawn significant attention in recent years, due to their highly tunable spin-orbit fields and intriguing interplay with lattice symmetry. Here, we perform first-principles calculations to determine the spin relaxation time (T1) and ensemble spin dephasing time ([Formula: see text]) in a prototype halide perovskite, CsPbBr3. To accurately capture spin dephasing in external magnetic fields we determine the Landé g-factor from first principles and take it into account in our calculations. These allow us to predict intrinsic spin lifetimes as an upper bound for experiments, identify the dominant spin relaxation pathways, and evaluate the dependence on temperature, external fields, carrier density, and impurities. We find that the Fröhlich interaction that dominates carrier relaxation contributes negligibly to spin relaxation, consistent with the spin-conserving nature of this interaction. Our theoretical approach may lead to new strategies to optimize spin and carrier transport properties.
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Affiliation(s)
- Junqing Xu
- Department of Physics, Hefei University of Technology, Hefei, Anhui, China
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA, USA
| | - Kejun Li
- Department of Physics, University of California, Santa Cruz, California, USA
| | - Uyen N Huynh
- Department of Physics and Astronomy, University of Utah, Salt Lake City, UT, USA
| | - Mayada Fadel
- Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Jinsong Huang
- Department of Applied Physical Sciences, University of North Carolina, Chapel Hill, NC, USA
| | - Ravishankar Sundararaman
- Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA.
| | - Valy Vardeny
- Department of Physics and Astronomy, University of Utah, Salt Lake City, UT, USA.
| | - Yuan Ping
- Department of Physics, University of California, Santa Cruz, California, USA.
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI, USA.
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4
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Abstract
Valley degrees of freedom in transition metal dichalcogenides thoroughly influence electron-phonon coupling and its nonequilibrium dynamics. We conducted a first-principles study of the quantum kinetics of chiral phonons following valley-selective carrier excitation with circularly polarized light. Our numerical investigations treat the ultrafast dynamics of electrons and phonons on equal footing within a parameter-free ab initio framework. We report the emergence of valley-polarized phonon populations in monolayer MoS2 that can be selectively excited at either the K or K' valleys depending on the light helicity. The resulting vibrational state is characterized by a distinctive chirality, which lifts time-reversal symmetry of the lattice on transient time scales. We show that chiral valley phonons can further lead to fingerprints of vibrational dichroism detectable by ultrafast diffuse scattering and persist beyond 10 ps. The valley polarization of nonequilibrium phonon populations could be exploited as an information carrier, thereby extending the paradigm of valleytronics to the domain of vibrational excitations.
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Affiliation(s)
- Yiming Pan
- Institut für Theoretische Physik und Astrophysik, Christian-Albrechts-Universität zu Kiel, D-24118 Kiel, Germany
| | - Fabio Caruso
- Institut für Theoretische Physik und Astrophysik, Christian-Albrechts-Universität zu Kiel, D-24118 Kiel, Germany
- Kiel Nano, Surface and Interface Science KiNSIS, Christian-Albrechts-Universität zu Kiel, D-24118 Kiel, Germany
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5
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Zhang C, Wang R, Mishra H, Liu Y. Two-Dimensional Semiconductors with High Intrinsic Carrier Mobility at Room Temperature. PHYSICAL REVIEW LETTERS 2023; 130:087001. [PMID: 36898124 DOI: 10.1103/physrevlett.130.087001] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Accepted: 01/25/2023] [Indexed: 06/18/2023]
Abstract
Two-dimensional semiconductors have demonstrated great potential for next-generation electronics and optoelectronics, however, the current 2D semiconductors suffer from intrinsically low carrier mobility at room temperature, which significantly limits their applications. Here we discover a variety of new 2D semiconductors with mobility 1 order of magnitude higher than the current ones and even higher than bulk silicon. The discovery was made by developing effective descriptors for computational screening of the 2D materials database, followed by high-throughput accurate calculation of the mobility using a state-of-the-art first-principles method that includes quadrupole scattering. The exceptional mobilities are explained by several basic physical features; particularly, we find a new feature: carrier-lattice distance, which is easy to calculate and correlates well with mobility. Our Letter opens up new materials for high performance device performance and/or exotic physics, and improves the understanding of the carrier transport mechanism.
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Affiliation(s)
- Chenmu Zhang
- Texas Materials Institute and Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Ruoyu Wang
- Texas Materials Institute and Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Himani Mishra
- Texas Materials Institute and Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Yuanyue Liu
- Texas Materials Institute and Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
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6
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Selhorst R, Yu Z, Moore D, Jiang J, Susner MA, Glavin NR, Pachter R, Terrones M, Maruyama B, Rao R. Precision Modification of Monolayer Transition Metal Dichalcogenides via Environmental E-Beam Patterning. ACS NANO 2023; 17:2958-2967. [PMID: 36689725 DOI: 10.1021/acsnano.2c11503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Layered Transition Metal Dichalcogenides (TMDs) are an important class of materials that exhibit a wide variety of optoelectronic properties. The ability to spatially tailor their expansive property-space (e.g., conduction behavior, optical emission, surface interactions) is of special interest for applications including, but not limited to, sensing, bioelectronics, and spintronics/valleytronics. Current methods of property modulation focus on the modification of the basal surfaces and edge sites of the TMDs by the introduction of defects, functionalization with organic or inorganic moieties, alloying, heterostructure formation, and phase engineering. A majority of these methods lack the resolution for the development of next-generation nanoscale devices or are limited in the types of functionalities useful for efficient TMD property modification. In this study, we utilize electron-beam patterning on monolayer TMDs (MoSe2, WSe2 and MoS2) in the presence of a pressure-controlled atmosphere of water vapor within an environmental scanning electron microscope (ESEM). A series of parametric studies show local optical and electronic property modification depending on acceleration voltage, beam current, pressure, and electron dose. The ultimate pattern resolution achieved is 67 ± 9 nm. Raman and photoluminescence spectroscopies coupled with Kelvin Probe Force Microscopy reveal electron dose-dependent p-doping in the patterned regions, which we attribute to functionalization from the products of water vapor radiolysis (oxygen and hydroxyl groups). The modulation of the work function through patterning matches well with Density Functional Theory modeling. Finally, post-functionalization of the patterned areas with an organic fluorophore demonstrates a robust method to achieve nanoscale functionalization with high fidelity.
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Affiliation(s)
- Ryan Selhorst
- Materials and Manufacturing Directorate, Air Force Research Laboratory, 2179 12th Street, Wright-Patterson Air Force Base, Dayton, Ohio 45433, United States
- UES Inc., 4401 Dayton-Xenia Rd., Dayton, Ohio 45433, United States
| | - Zhuohang Yu
- Department of Materials Science and Engineering, The Pennsylvania State University, 221 Steidle Building, University Park, Pennsylvania 16802, United States
| | - David Moore
- Materials and Manufacturing Directorate, Air Force Research Laboratory, 2179 12th Street, Wright-Patterson Air Force Base, Dayton, Ohio 45433, United States
| | - Jie Jiang
- Materials and Manufacturing Directorate, Air Force Research Laboratory, 2179 12th Street, Wright-Patterson Air Force Base, Dayton, Ohio 45433, United States
| | - Michael A Susner
- Materials and Manufacturing Directorate, Air Force Research Laboratory, 2179 12th Street, Wright-Patterson Air Force Base, Dayton, Ohio 45433, United States
| | - Nicholas R Glavin
- Materials and Manufacturing Directorate, Air Force Research Laboratory, 2179 12th Street, Wright-Patterson Air Force Base, Dayton, Ohio 45433, United States
| | - Ruth Pachter
- Materials and Manufacturing Directorate, Air Force Research Laboratory, 2179 12th Street, Wright-Patterson Air Force Base, Dayton, Ohio 45433, United States
| | - Mauricio Terrones
- Department of Materials Science and Engineering, The Pennsylvania State University, 221 Steidle Building, University Park, Pennsylvania 16802, United States
| | - Benji Maruyama
- Materials and Manufacturing Directorate, Air Force Research Laboratory, 2179 12th Street, Wright-Patterson Air Force Base, Dayton, Ohio 45433, United States
| | - Rahul Rao
- Materials and Manufacturing Directorate, Air Force Research Laboratory, 2179 12th Street, Wright-Patterson Air Force Base, Dayton, Ohio 45433, United States
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Bashir K, Bilal M, Amin B, Chen Y, Idrees M. Structural, electronic and thermoelectric properties of GeC and MXO (M = Ti, Zr and X = S, Se) monolayers and their van der Waals heterostructures. RSC Adv 2023; 13:9624-9635. [PMID: 36968037 PMCID: PMC10037300 DOI: 10.1039/d2ra07797c] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 01/13/2023] [Indexed: 03/26/2023] Open
Abstract
Vertical stacking of two-dimensional materials into layered van der Waals heterostructures is considered favourable for nanoelectronics and thermoelectric applications. In this work, we investigate the structural, electronic and thermoelectric properties of GeC and Janus monolayers MXO (M = Ti, Zr; X = S, Se) and their van der Waals (vdW) heterostructures using first-principles calculations. The values of binding energies, interlayer distances and thermal stability confirm the stability of these vdW heterostructures. The calculated band structure shows that GeC monolayer have a direct band gap while MXO (M = Ti, Zr; X = S, Se) and their van der Waals heterostructures show indirect band nature. Partial density of states confirms the type-II band alignment of GeC–MXY vdW heterostructures. Our results shows that ZrSeO (GeC) monolayers and GeC–ZrSO vdW heterostructures have higher power factor, making them promising for thermoelectric device applications. Calculated Seebeck coefficient (a) and (b) electrical conductivity (c) and (d) and power factor (e) and (f) of GeC–TiSO, GeC–TiSeO, GeC–ZrSO and GeC–ZrSeO vdW heterostructures for 300 K and 800 K, respectively.![]()
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Affiliation(s)
- Khadeeja Bashir
- Department of Physics, Abbottabad University of Science and TechnologyHavelianAbbottabad 22010Pakistan
| | - M. Bilal
- Department of Physics, Abbottabad University of Science and TechnologyHavelianAbbottabad 22010Pakistan
| | - B. Amin
- Department of Physics, Abbottabad University of Science and TechnologyHavelianAbbottabad 22010Pakistan
| | - Yuanping Chen
- School of Physics and Electronic Engineering, Jiangsu UniversityZhenjiang212013JiangsuChina
| | - M. Idrees
- School of Physics and Electronic Engineering, Jiangsu UniversityZhenjiang212013JiangsuChina
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8
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Wang X, Niu G, Jiang J, Sui L, Zeng X, Liu X, Zhang Y, Wu G, Yuan K, Yang X. Anomalous Dynamics of Defect-Assisted Phonon Recycling in Few-Layer Mo 0.5W 0.5S 2. J Phys Chem Lett 2022; 13:10395-10403. [PMID: 36318176 DOI: 10.1021/acs.jpclett.2c02935] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Alloying has emerged as a new strategy to tune the function of 2D transition metal dichalcogenides (TMDCs). However, the lack of research on the electrical and structural properties of these alloys limits their practical applications. Here, femtosecond transient absorption spectroscopy with pump pulse tunability is performed to elucidate the ultrafast carrier dynamics in the few-layer Mo0.5W0.5S2 prepared by the liquid phase exfoliation method. An anomalous rebleaching of the ground state is observed at high pump fluence by 3.1 eV excitation. We ascribe this rebleaching of the ground state to the mechanism that the carriers trapped in the defect are thermally excited back to the untrapped exciton state due to the phonon recycling, which hinders the dissipation of nonradiative energy, through comparative experiments and global analysis. Our findings demonstrate a novel energy transfer channel assisted by defect in few-layer TMDCs which is critical for their advanced applications.
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Affiliation(s)
- Xiaowei Wang
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- University of the Chinese Academy of Sciences, Beijing 100039, China
| | - Guangming Niu
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- Marine Engineering College, Dalian Maritime University, Dalian 116026, China
| | - Jutao Jiang
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- University of the Chinese Academy of Sciences, Beijing 100039, China
| | - Laizhi Sui
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Xiangyu Zeng
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China
| | - Xin Liu
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- Science College, Dalian Maritime University, Dalian 116026, China
| | - Yutong Zhang
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Guorong Wu
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Kaijun Yuan
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
| | - Xueming Yang
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
- Department of Chemistry, College of Science, Southern University of Science and Technology, Shenzhen 518055, China
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9
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Zhumagulov YV, Vagov A, Gulevich DR, Perebeinos V. Electrostatic and Environmental Control of the Trion Fine Structure in Transition Metal Dichalcogenide Monolayers. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:3728. [PMID: 36364505 PMCID: PMC9656490 DOI: 10.3390/nano12213728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 10/18/2022] [Accepted: 10/19/2022] [Indexed: 06/16/2023]
Abstract
Charged excitons or trions are essential for optical spectra in low-dimensional doped monolayers (ML) of transitional metal dichalcogenides (TMDC). Using a direct diagonalization of the three-body Hamiltonian, we calculate the low-lying trion states in four types of TMDC MLs as a function of doping and dielectric environment. We show that the fine structure of the trion is the result of the interplay between the spin-valley fine structure of the single-particle bands and the exchange interaction. We demonstrate that by variations of the doping and dielectric environment, the fine structure of the trion energy can be tuned, leading to anticrossing of the bright and dark states, with substantial implications for the optical spectra of the TMDC ML.
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Affiliation(s)
| | - Alexei Vagov
- Faculty of Physics, National Research University Higher School of Economics, 101000 Moscow, Russia
| | | | - Vasili Perebeinos
- Department of Electrical Engineering, University at Buffalo, The State University of New York, Buffalo, NY 14260, USA
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10
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Yu S, Tang J, Wang Y, Xu F, Li X, Wang X. Recent advances in two-dimensional ferromagnetism: strain-, doping-, structural- and electric field-engineering toward spintronic applications. SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS 2022; 23:140-160. [PMID: 35185390 PMCID: PMC8856075 DOI: 10.1080/14686996.2022.2030652] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 01/03/2022] [Accepted: 01/09/2022] [Indexed: 05/27/2023]
Abstract
Since the first report on truly two-dimensional (2D) magnetic materials in 2017, a wide variety of merging 2D magnetic materials with unusual physical characteristics have been discovered and thus provide an effective platform for exploring the associated novel 2D spintronic devices, which have been made significant progress in both theoretical and experimental studies. Herein, we make a comprehensive review on the recent scientific endeavors and advances on the various engineering strategies on 2D ferromagnets, such as strain-, doping-, structural- and electric field-engineering, toward practical spintronic applications, including spin tunneling junctions, spin field-effect transistors and spin logic gate, etc. In the last, we discuss on current challenges and future opportunities in this field, which may provide useful guidelines for scientists who are exploring the fundamental physical properties and practical spintronic devices of low-dimensional magnets.
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Affiliation(s)
- Sheng Yu
- Institute of Information Technology, Shenzhen Institute of Information Technology, Shenzhen, China
- Institute for Advanced Study, Shenzhen University, Shenzhen, China
| | - Junyu Tang
- Department of Physics and Astronomy, University of California, Riverside, CA, USA
| | - Yu Wang
- Institute for Advanced Study, Shenzhen University, Shenzhen, China
| | - Feixiang Xu
- Institute for Advanced Study, Shenzhen University, Shenzhen, China
| | - Xiaoguang Li
- Institute for Advanced Study, Shenzhen University, Shenzhen, China
| | - Xinzhong Wang
- Institute of Information Technology, Shenzhen Institute of Information Technology, Shenzhen, China
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11
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Xu J, Takenaka H, Habib A, Sundararaman R, Ping Y. Giant Spin Lifetime Anisotropy and Spin-Valley Locking in Silicene and Germanene from First-Principles Density-Matrix Dynamics. NANO LETTERS 2021; 21:9594-9600. [PMID: 34767368 DOI: 10.1021/acs.nanolett.1c03345] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Through first-principles real-time density-matrix (FPDM) dynamics simulations, we investigated spin relaxation due to electron-phonon and electron-impurity scatterings with spin-orbit coupling (SOC) in two-dimensional Dirac materials silicene and germanene at finite temperatures. We discussed the applicability of conventional descriptions of spin relaxation mechanisms by Elliott-Yafet (EY) and D'yakonov-Perel' (DP) compared to the FPDM method, which is determined by a complex interplay of intrinsic SOC, external fields, and scattering strength. For example, the electric field dependence of the spin lifetime by FPDM is close to the DP mechanism for silicene at room temperature but similar to the EY mechanism for germanene. Because of its stronger SOC strength and buckled structure in contrast to graphene, germanene has a giant spin lifetime anisotropy and spin-valley locking effect under nonzero Ez and low temperatures. More importantly, germanene has a long spin lifetime (∼100 ns at 50 K) and an ultrahigh carrier mobility, making it advantageous for spin-valleytronic applications.
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Affiliation(s)
- Junqing Xu
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, United States
| | - Hiroyuki Takenaka
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, United States
| | - Adela Habib
- Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, New York 12180, United States
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87544, United States
| | - Ravishankar Sundararaman
- Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, New York 12180, United States
| | - Yuan Ping
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, United States
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12
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Paez-Ornelas JI, Ponce-Pérez R, Fernández-Escamilla HN, Hoat DM, Murillo-Bracamontes EA, Moreno-Armenta MG, Galván DH, Guerrero-Sánchez J. The effect of shape and size in the stability of triangular Janus MoSSe quantum dots. Sci Rep 2021; 11:21061. [PMID: 34702822 PMCID: PMC8548305 DOI: 10.1038/s41598-021-00287-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 10/08/2021] [Indexed: 11/09/2022] Open
Abstract
Asymmetric Janus transition metal dichalcogenide MoSSe is a promising catalytic material due to the intrinsic in-plane dipole of its opposite faces. The atomic description of the structures observed by experimental techniques is relevant to tuning and optimizing its surface reaction processes. Furthermore, the experimentally observed triangular morphologies in MoSSe suggest that an analysis of the chemical environment of its edges is vital to understand its reactivity. Here we analyze the size-shape stability among different triangular structures-quantum- dots proposed from the ideal S(-1010) and Mo(10-10) terminations. Our stability analysis evidenced that the S–Se termination is more stable than Mo; moreover, as the size of the quantum dot increases, its stability increases as well. Besides, a trend is observed, with the appearance of elongated Mo-S/Se bonds at symmetric positions of the edges. Tersoff–Hamann scanning tunneling microscopy images for both faces of the stablest models are presented. Electrostatic potential isosurfaces denote that the basal plane on the S face of both configurations remains the region with more electron density concentration. These results point toward the differentiated activity over both faces. Finally, our study denotes the exact atomic arrangement on the edges of MoSSe quantum dots corresponding with the formation of S/Se dimers who decorates the edges and their role along with the faces as catalytic sites.
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Affiliation(s)
- J I Paez-Ornelas
- Centro de Investigación Científica y de Educación Superior de Ensenada, Ensenada Baja California, 22800, Mexico. .,Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México, Apartado Postal 14, Ensenada Baja California, 22800, Mexico.
| | - R Ponce-Pérez
- Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México, Apartado Postal 14, Ensenada Baja California, 22800, Mexico
| | - H N Fernández-Escamilla
- Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México, Apartado Postal 14, Ensenada Baja California, 22800, Mexico
| | - D M Hoat
- Institute of Theoretical and Applied Research, Duy Tan University, Hanoi, 100000, Viet Nam.,Faculty of Natural Sciences, Duy Tan University, Da Nang, 550000, Viet Nam
| | - E A Murillo-Bracamontes
- Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México, Apartado Postal 14, Ensenada Baja California, 22800, Mexico
| | - María G Moreno-Armenta
- Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México, Apartado Postal 14, Ensenada Baja California, 22800, Mexico
| | - Donald H Galván
- Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México, Apartado Postal 14, Ensenada Baja California, 22800, Mexico
| | - J Guerrero-Sánchez
- Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México, Apartado Postal 14, Ensenada Baja California, 22800, Mexico.
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13
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Tian X, Yan X, Varnavides G, Yuan Y, Kim DS, Ciccarino CJ, Anikeeva P, Li MY, Li LJ, Narang P, Pan X, Miao J. Capturing 3D atomic defects and phonon localization at the 2D heterostructure interface. SCIENCE ADVANCES 2021; 7:eabi6699. [PMID: 34524846 PMCID: PMC8443181 DOI: 10.1126/sciadv.abi6699] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 07/22/2021] [Indexed: 06/13/2023]
Abstract
The three-dimensional (3D) local atomic structures and crystal defects at the interfaces of heterostructures control their electronic, magnetic, optical, catalytic, and topological quantum properties but have thus far eluded any direct experimental determination. Here, we use atomic electron tomography to determine the 3D local atomic positions at the interface of a MoS2-WSe2 heterojunction with picometer precision and correlate 3D atomic defects with localized vibrational properties at the epitaxial interface. We observe point defects, bond distortion, and atomic-scale ripples and measure the full 3D strain tensor at the heterointerface. By using the experimental 3D atomic coordinates as direct input to first-principles calculations, we reveal new phonon modes localized at the interface, which are corroborated by spatially resolved electron energy-loss spectroscopy. We expect that this work will pave the way for correlating structure-property relationships of a wide range of heterostructure interfaces at the single-atom level.
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Affiliation(s)
- Xuezeng Tian
- Department of Physics and Astronomy and California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Xingxu Yan
- Department of Materials Science and Engineering, University of California, Irvine, Irvine, CA 92697, USA
- Irvine Materials Research Institute, University of California, Irvine, Irvine, CA 92697, USA
| | - Georgios Varnavides
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Yakun Yuan
- Department of Physics and Astronomy and California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Dennis S. Kim
- Department of Physics and Astronomy and California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Christopher J. Ciccarino
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Polina Anikeeva
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Ming-Yang Li
- Physical Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia
| | - Lain-Jong Li
- Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong
| | - Prineha Narang
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Xiaoqing Pan
- Department of Materials Science and Engineering, University of California, Irvine, Irvine, CA 92697, USA
- Irvine Materials Research Institute, University of California, Irvine, Irvine, CA 92697, USA
- Department of Physics and Astronomy, University of California, Irvine, Irvine, CA 92697, USA
| | - Jianwei Miao
- Department of Physics and Astronomy and California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
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14
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Xu S, Si C, Li Y, Gu BL, Duan W. Valley Depolarization Dynamics in Monolayer Transition-Metal Dichalcogenides: Role of the Satellite Valley. NANO LETTERS 2021; 21:1785-1791. [PMID: 33586443 DOI: 10.1021/acs.nanolett.0c04670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The valley depolarization dynamics of free holes in monolayer transition-metal dichalcogenides are studied by solving the Boltzmann transport equation in real time fully ab inito. While monolayer MoSe2, WS2, WSe2, and MoTe2 possess long hole valley lifetimes due to the spin-valley locking effect, monolayer MoS2 unexpectedly shows ultrafast valley dynamics, with a hole valley lifetime two orders of magnitude shorter than those of the above four materials at room temperature. It is further revealed that the existence of the satellite Γ valley in MoS2 provides an additional hole relaxation path where the Γ valley acts as an intermediate in the hole relaxation between primary K' and K valleys, and moreover, the strong scattering between primary and satellite valleys ensures the ultrafast valley depolarization. By uncovering the pivotal role of the satellite valley, our results may have significant implications for finely controlling valley depolarization in the multivalley materials.
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Affiliation(s)
- Shengnan Xu
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, People's Republic of China
- Collaborative Innovation Center of Quantum Matter, Beijing 100084, People's Republic of China
| | - Chen Si
- School of Materials Science and Engineering, Beihang University, Beijing 100191, People's Republic of China
| | - Yang Li
- Beijing Computational Science Research Center, Beijing 100193, People's Republic of China
| | - Bing-Lin Gu
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, People's Republic of China
- Collaborative Innovation Center of Quantum Matter, Beijing 100084, People's Republic of China
- Institute for Advanced Study, Tsinghua University, Beijing 100084, People's Republic of China
| | - Wenhui Duan
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, People's Republic of China
- Collaborative Innovation Center of Quantum Matter, Beijing 100084, People's Republic of China
- Institute for Advanced Study, Tsinghua University, Beijing 100084, People's Republic of China
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15
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Wang Y, Wei W, Li F, Lv X, Huang B, Dai Y. Valley polarization caused by crystalline symmetry breaking. MATERIALS HORIZONS 2021; 8:244-249. [PMID: 34874021 DOI: 10.1039/d0mh01441a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
In two-dimensional (2D) hexagonal lattices with inversion asymmetry, time-reversal (T) connected valleys are at the center of current valleytronic research. In order to trigger valley polarization, dynamical processes and/or magnetism have been considered. In this work, we propose a new mechanism, valley-contrasting sublattice polarization (VCSP), to polarize valleys by reducing the crystalline symmetry that connects the valleys. In our mechanism, significant valley polarization could be readily generated without magnetism, an electric field, or an optical process. Based on tight-binding model analysis and first-principle calculations, the control of valley polarization via crystalline symmetry can be successfully realized in concrete LaOBiS2 polytypes with Peierls-like structure distortion. Our results provide an unprecedented possibility for exploring valley-contrasting physics.
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Affiliation(s)
- Yuanyuan Wang
- 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.
| | - Fengping Li
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China.
| | - Xingshuai Lv
- 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.
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16
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Head-Marsden K, Flick J, Ciccarino CJ, Narang P. Quantum Information and Algorithms for Correlated Quantum Matter. Chem Rev 2020; 121:3061-3120. [PMID: 33326218 DOI: 10.1021/acs.chemrev.0c00620] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Discoveries in quantum materials, which are characterized by the strongly quantum-mechanical nature of electrons and atoms, have revealed exotic properties that arise from correlations. It is the promise of quantum materials for quantum information science superimposed with the potential of new computational quantum algorithms to discover new quantum materials that inspires this Review. We anticipate that quantum materials to be discovered and developed in the next years will transform the areas of quantum information processing including communication, storage, and computing. Simultaneously, efforts toward developing new quantum algorithmic approaches for quantum simulation and advanced calculation methods for many-body quantum systems enable major advances toward functional quantum materials and their deployment. The advent of quantum computing brings new possibilities for eliminating the exponential complexity that has stymied simulation of correlated quantum systems on high-performance classical computers. Here, we review new algorithms and computational approaches to predict and understand the behavior of correlated quantum matter. The strongly interdisciplinary nature of the topics covered necessitates a common language to integrate ideas from these fields. We aim to provide this common language while weaving together fields across electronic structure theory, quantum electrodynamics, algorithm design, and open quantum systems. Our Review is timely in presenting the state-of-the-art in the field toward algorithms with nonexponential complexity for correlated quantum matter with applications in grand-challenge problems. Looking to the future, at the intersection of quantum information science and algorithms for correlated quantum matter, we envision seminal advances in predicting many-body quantum states and describing excitonic quantum matter and large-scale entangled states, a better understanding of high-temperature superconductivity, and quantifying open quantum system dynamics.
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Affiliation(s)
- Kade Head-Marsden
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Johannes Flick
- Center for Computational Quantum Physics, Flatiron Institute, New York, New York 10010, United States
| | - Christopher J Ciccarino
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States.,Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Prineha Narang
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
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17
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Tian X, Kim DS, Yang S, Ciccarino CJ, Gong Y, Yang Y, Yang Y, Duschatko B, Yuan Y, Ajayan PM, Idrobo JC, Narang P, Miao J. Correlating the three-dimensional atomic defects and electronic properties of two-dimensional transition metal dichalcogenides. NATURE MATERIALS 2020; 19:867-873. [PMID: 32152562 DOI: 10.1038/s41563-020-0636-5] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 02/11/2020] [Indexed: 06/10/2023]
Abstract
The electronic, optical and chemical properties of two-dimensional transition metal dichalcogenides strongly depend on their three-dimensional atomic structure and crystal defects. Using Re-doped MoS2 as a model system, here we present scanning atomic electron tomography as a method to determine three-dimensional atomic positions as well as positions of crystal defects such as dopants, vacancies and ripples with a precision down to 4 pm. We measure the three-dimensional bond distortion and local strain tensor induced by single dopants. By directly providing these experimental three-dimensional atomic coordinates to density functional theory, we obtain more accurate electronic band structures than derived from conventional density functional theory calculations that relies on relaxed three-dimensional atomic coordinates. We anticipate that scanning atomic electron tomography not only will be generally applicable to determine the three-dimensional atomic coordinates of two-dimensional materials, but also will enable ab initio calculations to better predict the physical, chemical and electronic properties of these materials.
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Affiliation(s)
- Xuezeng Tian
- Department of Physics & Astronomy and California NanoSystems Institute, University of California, Los Angeles, CA, USA
| | - Dennis S Kim
- Department of Physics & Astronomy and California NanoSystems Institute, University of California, Los Angeles, CA, USA
| | - Shize Yang
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, USA
- Eyring Materials Center, Arizona State University, Tempe, AZ, USA
| | - Christopher J Ciccarino
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Yongji Gong
- Department of Materials Science and NanoEngineering, Rice University, Houston, TX, USA
| | - Yongsoo Yang
- Department of Physics & Astronomy and California NanoSystems Institute, University of California, Los Angeles, CA, USA
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon, Korea
| | - Yao Yang
- Department of Physics & Astronomy and California NanoSystems Institute, University of California, Los Angeles, CA, USA
| | - Blake Duschatko
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Yakun Yuan
- Department of Physics & Astronomy and California NanoSystems Institute, University of California, Los Angeles, CA, USA
| | - Pulickel M Ajayan
- Department of Materials Science and NanoEngineering, Rice University, Houston, TX, USA
| | - Juan Carlos Idrobo
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Prineha Narang
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Jianwei Miao
- Department of Physics & Astronomy and California NanoSystems Institute, University of California, Los Angeles, CA, USA.
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18
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Linardy E, Yadav D, Vella D, Verzhbitskiy IA, Watanabe K, Taniguchi T, Pauly F, Trushin M, Eda G. Harnessing Exciton-Exciton Annihilation in Two-Dimensional Semiconductors. NANO LETTERS 2020; 20:1647-1653. [PMID: 32078334 DOI: 10.1021/acs.nanolett.9b04756] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Strong many-body interactions in two-dimensional (2D) semiconductors give rise to efficient exciton-exciton annihilation (EEA). This process is expected to result in the generation of unbound high energy carriers. Here, we report an unconventional photoresponse of van der Waals heterostructure devices resulting from efficient EEA. Our heterostructures, which consist of monolayer transition metal dichalcogenide (TMD), hexagonal boron nitride (hBN), and few-layer graphene, exhibit photocurrent when photoexcited carriers possess sufficient energy to overcome the high energy barrier of hBN. Interestingly, we find that the device exhibits moderate photocurrent quantum efficiency even when the semiconducting TMD layer is excited at its ground exciton resonance despite the high exciton binding energy and large transport barrier. Using ab initio calculations, we show that EEA yields highly energetic electrons and holes with unevenly distributed energies depending on the scattering condition. Our findings highlight the dominant role of EEA in determining the photoresponse of 2D semiconductor optoelectronic devices.
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Affiliation(s)
- Eric Linardy
- Department of Physics, Faculty of Science, National University of Singapore, 2 Science Drive 3, Singapore 117551
- Centre for Advanced 2D Materials, National University of Singapore, 6 Science Drive 2, Singapore 117546
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, 21 Lower Kent Ridge, Singapore 119077, Singapore
| | - Dinesh Yadav
- Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
| | - Daniele Vella
- Department of Physics, Faculty of Science, National University of Singapore, 2 Science Drive 3, Singapore 117551
- Centre for Advanced 2D Materials, National University of Singapore, 6 Science Drive 2, Singapore 117546
| | - Ivan A Verzhbitskiy
- Department of Physics, Faculty of Science, National University of Singapore, 2 Science Drive 3, Singapore 117551
- Centre for Advanced 2D Materials, National University of Singapore, 6 Science Drive 2, Singapore 117546
| | - Kenji Watanabe
- National Institute for Material Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- National Institute for Material Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Fabian Pauly
- Okinawa Institute of Science and Technology Graduate University, Onna-son, Okinawa 904-0495, Japan
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
| | - Maxim Trushin
- Centre for Advanced 2D Materials, National University of Singapore, 6 Science Drive 2, Singapore 117546
| | - Goki Eda
- Department of Physics, Faculty of Science, National University of Singapore, 2 Science Drive 3, Singapore 117551
- Centre for Advanced 2D Materials, National University of Singapore, 6 Science Drive 2, Singapore 117546
- Department of Chemistry, Faculty of Science, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
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19
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Luo Y, Zhao G, Wang S. The electron-phonon scattering and carrier mobility in monolayer AsSb. Phys Chem Chem Phys 2020; 22:5688-5692. [PMID: 32103226 DOI: 10.1039/c9cp06945c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Through first-principles calculations, the electron-phonon scattering of two-dimensional monolayer AsSb is investigated. The Boltzmann transport equation is used to compute the phonon limited carrier mobility. We find that the optical phonon scattering rates are much larger than acoustic ones around the valence band maximum (VBM) and the conduction band minimum (CBM). The phonon-decomposed scattering results show that transverse optical (TO) phonon modes dominate the scattering around VBM, while longitudinal and out-of-plane acoustic modes contribute mostly to the scattering at higher energy. TO phonon modes dominate the scattering for electrons over all energy level, and the electron-phonon matrix element analysis verified the results. Finally, we observed that the largest mean free paths for hot holes and hot electrons are 20 nm and 8 nm, respectively. That is the best range to extract the hot holes and hot electrons. More interestingly, owing to the in-pane net dipole moment of AsSb, the intrinsic electron/hole mobility of AsSb are 38/50 cm2 V-1 s-1, which are less than monolayer arsenene and antimonene.
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Affiliation(s)
- Ying Luo
- School of Physical Science and Technology, Inner Mongolia University, Hohhot, 010021, China.
| | - Guojun Zhao
- School of Physical Science and Technology, Inner Mongolia University, Hohhot, 010021, China.
| | - Shudong Wang
- School of Physical Science and Technology, Inner Mongolia University, Hohhot, 010021, China.
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20
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Kapuściński P, Vaclavkova D, Grzeszczyk M, Slobodeniuk AO, Nogajewski K, Bartos M, Watanabe K, Taniguchi T, Faugeras C, Babiński A, Potemski M, Molas MR. Valley polarization of singlet and triplet trions in a WS2 monolayer in magnetic fields. Phys Chem Chem Phys 2020; 22:19155-19161. [DOI: 10.1039/d0cp02737e] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Magnetic field induced valley polarization of carriers is substantially different for the absorption and emission response of a WS2 monolayer.
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21
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Wang Y, Wei W, Wang H, Mao N, Li F, Huang B, Dai Y. Janus TiXY Monolayers with Tunable Berry Curvature. J Phys Chem Lett 2019; 10:7426-7432. [PMID: 31722532 DOI: 10.1021/acs.jpclett.9b02853] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Up to now, two-dimensional (2D) materials with both valley polarization and the Rashba effect are still rare. In this work, a new kind of Janus monolayers TiXY (X ≠ Y, X/Y = Cl, Br, I) is demonstrated to have physical properties of benefit for spintronics and valleytronics. In particular, Janus TiBrI shows Zeeman-type spin splitting of 70 meV, large Berry curvature of 106.22 bohr2, and, at the same time, a large Rashba parameter of 147.95 meV Å. On the basis of k·p perturbation theory, we proposed that the Berry curvature can be adjusted by changing the lattice parameter, which will greatly improve the transverse velocities of carriers and promote the efficiency of the valley Hall device. Biaxial strain from -2.5 to 2.5% was applied on Janus TiBrI to verify the theory mentioned above, and a general relationship between the Berry curvature and lattice constant was obtained.
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Affiliation(s)
- Yuanyuan Wang
- 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
| | - Hao Wang
- School of Physics, State Key Laboratory of Crystal Materials , Shandong University , Jinan 250100 , China
| | - Ning Mao
- School of Physics, State Key Laboratory of Crystal Materials , Shandong University , Jinan 250100 , China
| | - Fengping Li
- 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
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22
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Su MN, Ciccarino CJ, Kumar S, Dongare PD, Hosseini Jebeli SA, Renard D, Zhang Y, Ostovar B, Chang WS, Nordlander P, Halas NJ, Sundararaman R, Narang P, Link S. Ultrafast Electron Dynamics in Single Aluminum Nanostructures. NANO LETTERS 2019; 19:3091-3097. [PMID: 30935208 DOI: 10.1021/acs.nanolett.9b00503] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Aluminum nanostructures are a promising alternative material to noble metal nanostructures for several photonic and catalytic applications, but their ultrafast electron dynamics remain elusive. Here, we combine single-particle transient extinction spectroscopy and parameter-free first-principles calculations to investigate the non-equilibrium carrier dynamics in aluminum nanostructures. Unlike gold nanostructures, we find the sub-picosecond optical response of lithographically fabricated aluminum nanodisks to be more sensitive to the lattice temperature than the electron temperature. We assign the rise in the transient transmission to electron-phonon coupling with a pump-power-independent lifetime of 500 ± 100 fs and theoretically confirm this strong electron-phonon coupling behavior. We also measure electron-phonon lifetimes in chemically synthesized aluminum nanocrystals and find them to be even longer (1.0 ± 0.1 ps) than for the nanodisks. We also observe a rise and decay in the transient transmissions with amplitudes that scale with the surface-to-volume ratio of the aluminum nanodisks, implying a possible hot carrier trapping and detrapping at the native oxide shell-metal core interface.
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Affiliation(s)
| | | | - Sushant Kumar
- Department of Materials Science and Engineering , Rensselaer Polytechnic Institute , Troy , New York 12180 , United States
| | | | | | | | | | | | | | | | | | - Ravishankar Sundararaman
- Department of Materials Science and Engineering , Rensselaer Polytechnic Institute , Troy , New York 12180 , United States
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23
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Ciccarino CJ, Chakraborty C, Englund DR, Narang P. Carrier dynamics and spin-valley-layer effects in bilayer transition metal dichalcogenides. Faraday Discuss 2019; 214:175-188. [PMID: 30816899 DOI: 10.1039/c8fd00159f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Transition metal dichalcogenides are an interesting class of low dimensional materials in mono- and few-layer form with diverse applications in valleytronic, optoelectronic and quantum devices. Therefore, the general nature of the band-edges and the interplay with valley dynamics is important from a fundamental and technological standpoint. Bilayers introduce interlayer coupling effects which can have a significant impact on the valley polarization. The combined effect of spin-orbit and interlayer coupling can strongly modify the band structure, phonon interactions and overall carrier dynamics in the material. Here we use first-principles calculations of electron-electron and electron-phonon interactions to investigate bilayer MoS2 and WSe2 in both the AA' and AB stacking configurations. We find that in addition to spin-orbit coupling, interlayer interactions present in the two configurations significantly alter the near-band-edge dynamics. Scattering lifetimes and dynamic behavior are highly material-dependent, despite the similarities and typical trends in TMDCs. Additionally, we capture significant differences in dynamics for the AA' and AB stacking configurations, with lifetime values differing by up to an order of magnitude between them for MoS2. Further, we evaluate the valley polarization times and find that maximum lifetimes at room temperature are of the scale of 1 picosecond for WSe2 in the AB orientation. These results present a pathway to understanding complex heterostructure configurations and 'magic angle' physics in TMDCs.
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Affiliation(s)
- Christopher J Ciccarino
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA. and Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Chitraleema Chakraborty
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA. and Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Dirk R Englund
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Prineha Narang
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA.
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24
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Rivera N, Christensen T, Narang P. Phonon Polaritonics in Two-Dimensional Materials. NANO LETTERS 2019; 19:2653-2660. [PMID: 30892900 DOI: 10.1021/acs.nanolett.9b00518] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Extreme confinement of electromagnetic energy by phonon polaritons holds the promise of strong and new forms of control over the dynamics of matter. To bring such control to the atomic-scale limit, it is important to consider phonon polaritons in two-dimensional (2D) systems. Recent studies have pointed out that in 2D, splitting between longitudinal and transverse optical (LO and TO) phonons is absent at the Γ point, even for polar materials. Does this lack of LO-TO splitting imply the absence of a phonon polariton in polar monolayers? To answer this, we connect the microscopic phonon properties with the macroscopic electromagnetic response. Specifically, we derive a first-principles expression for the conductivity of a polar monolayer specified by the wave-vector-dependent LO and TO phonon dispersions. In the long-wavelength (local) limit, we find a universal form for the conductivity in terms of the LO phonon frequency at the Γ point, its lifetime, and the group velocity of the LO phonon. Our analysis reveals that the phonon polariton of 2D is simply the LO phonon of the 2D system. For the specific example of hexagonal boron nitride (hBN), we estimate the confinement and propagation losses of the LO phonons, finding that high confinement and reasonable propagation quality factors coincide in regions that may be difficult to detect with current near-field optical microscopy techniques. Finally, we study the interaction of external emitters with 2D hBN nanostructures, finding an extreme enhancement of spontaneous emission due to coupling with localized 2D phonon polaritons and the possibility of multimode strong and ultrastrong coupling between an external emitter and hBN phonons. This may lead to the design of new hybrid states of electrons and phonons based on strong coupling.
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Affiliation(s)
- Nicholas Rivera
- John A. Paulson School of Engineering and Applied Sciences , Harvard University , Cambridge , Massachusetts 02139 , United States
- Department of Physics , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
| | - Thomas Christensen
- Department of Physics , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
| | - Prineha Narang
- John A. Paulson School of Engineering and Applied Sciences , Harvard University , Cambridge , Massachusetts 02139 , United States
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