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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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Park J, Zhou JJ, Luo Y, Bernardi M. Predicting Phonon-Induced Spin Decoherence from First Principles: Colossal Spin Renormalization in Condensed Matter. PHYSICAL REVIEW LETTERS 2022; 129:197201. [PMID: 36399728 DOI: 10.1103/physrevlett.129.197201] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 08/11/2022] [Indexed: 06/16/2023]
Abstract
Developing a microscopic understanding of spin decoherence is essential to advancing quantum technologies. Electron spin decoherence due to atomic vibrations (phonons) plays a special role as it sets an intrinsic limit to the performance of spin-based quantum devices. Two main sources of phonon-induced spin decoherence-the Elliott-Yafet and Dyakonov-Perel mechanisms-have distinct physical origins and theoretical treatments. Here, we show calculations that unify their modeling and enable accurate predictions of spin relaxation and precession in semiconductors. We compute the phonon-dressed vertex of the spin-spin correlation function with a treatment analogous to the calculation of the anomalous electron magnetic moment in QED. We find that the vertex correction provides a giant renormalization of the electron spin dynamics in solids, greater by many orders of magnitude than the corresponding correction from photons in vacuum. Our Letter demonstrates a general approach for quantitative analysis of spin decoherence in materials, advancing the quest for spin-based quantum technologies.
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Affiliation(s)
- Jinsoo Park
- Department of Applied Physics and Materials Science, California Institute of Technology, Pasadena, California 91125, USA
| | - Jin-Jian Zhou
- School of Physics, Beijing Institute of Technology, Beijing 100081, China
| | - Yao Luo
- Department of Applied Physics and Materials Science, California Institute of Technology, Pasadena, California 91125, USA
| | - Marco Bernardi
- Department of Physics, California Institute of Technology, Pasadena, California 91125, USA
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Smoleński T, Watanabe K, Taniguchi T, Kroner M, Imamoğlu A. Spin-Valley Relaxation and Exciton-Induced Depolarization Dynamics of Landau-Quantized Electrons in MoSe_{2} Monolayer. PHYSICAL REVIEW LETTERS 2022; 128:127402. [PMID: 35394309 DOI: 10.1103/physrevlett.128.127402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 12/05/2021] [Accepted: 01/26/2022] [Indexed: 06/14/2023]
Abstract
Nonequilibrium dynamics of strongly correlated systems constitutes a fascinating problem of condensed matter physics with many open questions. Here, we investigate the relaxation dynamics of Landau-quantized electron system into spin-valley polarized ground state in a gate-tunable MoSe_{2} monolayer subjected to a strong magnetic field. The system is driven out of equilibrium with optically injected excitons that depolarize the electron spins and the subsequent electron spin-valley relaxation is probed in time-resolved experiments. We demonstrate that both the relaxation and light-induced depolarization rates at millikelvin temperatures sensitively depend on the Landau level filling factor: the relaxation is enhanced whenever the electrons form an integer quantum Hall liquid and slows down appreciably at noninteger fillings, while the depolarization rate exhibits an opposite behavior. Our findings suggest that spin-valley dynamics may be used as a tool to investigate the interplay between the effects of disorder and strong interactions in the electronic ground state.
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Affiliation(s)
- T Smoleński
- Institute for Quantum Electronics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - K Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan
| | - T Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan
| | - M Kroner
- Institute for Quantum Electronics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - A Imamoğlu
- Institute for Quantum Electronics, ETH Zürich, CH-8093 Zürich, Switzerland
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Robert C, Park S, Cadiz F, Lombez L, Ren L, Tornatzky H, Rowe A, Paget D, Sirotti F, Yang M, Van Tuan D, Taniguchi T, Urbaszek B, Watanabe K, Amand T, Dery H, Marie X. Spin/valley pumping of resident electrons in WSe 2 and WS 2 monolayers. Nat Commun 2021; 12:5455. [PMID: 34526493 PMCID: PMC8443707 DOI: 10.1038/s41467-021-25747-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 08/31/2021] [Indexed: 11/09/2022] Open
Abstract
Monolayers of transition metal dichalcogenides are ideal materials to control both spin and valley degrees of freedom either electrically or optically. Nevertheless, optical excitation mostly generates excitons species with inherently short lifetime and spin/valley relaxation time. Here we demonstrate a very efficient spin/valley optical pumping of resident electrons in n-doped WSe2 and WS2 monolayers. We observe that, using a continuous wave laser and appropriate doping and excitation densities, negative trion doublet lines exhibit circular polarization of opposite sign and the photoluminescence intensity of the triplet trion is more than four times larger with circular excitation than with linear excitation. We interpret our results as a consequence of a large dynamic polarization of resident electrons using circular light.
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Affiliation(s)
- Cedric Robert
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077, Toulouse, France.
| | - Sangjun Park
- Physique de la matière condensée, Ecole Polytechnique, CNRS, IP Paris, 91128, Paris, Palaiseau, France
| | - Fabian Cadiz
- Physique de la matière condensée, Ecole Polytechnique, CNRS, IP Paris, 91128, Paris, Palaiseau, France.
| | - Laurent Lombez
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077, Toulouse, France
| | - Lei Ren
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077, Toulouse, France
| | - Hans Tornatzky
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077, Toulouse, France
| | - Alistair Rowe
- Physique de la matière condensée, Ecole Polytechnique, CNRS, IP Paris, 91128, Paris, Palaiseau, France
| | - Daniel Paget
- Physique de la matière condensée, Ecole Polytechnique, CNRS, IP Paris, 91128, Paris, Palaiseau, France
| | - Fausto Sirotti
- Physique de la matière condensée, Ecole Polytechnique, CNRS, IP Paris, 91128, Paris, Palaiseau, France
| | - Min Yang
- Department of Electrical and Computer Engineering, University of Rochester, Rochester, NY, 14627, USA
| | - Dinh Van Tuan
- Department of Electrical and Computer Engineering, University of Rochester, Rochester, NY, 14627, USA
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-00044, Japan
| | - Bernhard Urbaszek
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077, Toulouse, France
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-00044, Japan
| | - Thierry Amand
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077, Toulouse, France
| | - Hanan Dery
- Department of Electrical and Computer Engineering, University of Rochester, Rochester, NY, 14627, USA
- Department of Physics, University of Rochester, Rochester, NY, 14627, USA
| | - Xavier Marie
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Av. Rangueil, 31077, Toulouse, France.
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Kozlov GG, Fomin AA, Petrov MY, Ryzhov II, Zapasskii VS. Raman scattering model of the spin noise. OPTICS EXPRESS 2021; 29:4770-4782. [PMID: 33726026 DOI: 10.1364/oe.415034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 01/18/2021] [Indexed: 06/12/2023]
Abstract
The mechanism of formation of the polarimetric signal observed in the spin noise spectroscopy (SNS) is analyzed from the viewpoint of the light scattering theory. A rigorous calculation of the polarimetric signal (Faraday rotation or ellipticity) recorded in the SNS is presented in the approximation of single scattering. We show that it is most correctly to consider this noise as a result of scattering of the probe light beam by fluctuating susceptibility of the medium. Fluctuations of the gyrotropic (antisymmetric) part of the susceptibility tensor lead to appearance of the typical for the SNS Faraday rotation noise at the Larmor frequency. At the same time, fluctuations of linear anisotropy of the medium (symmetric part of the susceptibility tensor) give rise to the ellipticity noise of the probe beam spectrally localized at the double Larmor frequency. The results of the theoretical analysis well agree with the experimental data on the ellipticity noise in cesium vapor.
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Ersfeld M, Volmer F, Rathmann L, Kotewitz L, Heithoff M, Lohmann M, Yang B, Watanabe K, Taniguchi T, Bartels L, Shi J, Stampfer C, Beschoten B. Unveiling Valley Lifetimes of Free Charge Carriers in Monolayer WSe 2. NANO LETTERS 2020; 20:3147-3154. [PMID: 32202802 DOI: 10.1021/acs.nanolett.9b05138] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We report on nanosecond-long, gate-dependent valley lifetimes of free charge carriers in monolayer WSe2, unambiguously identified by the combination of time-resolved Kerr rotation and electrical transport measurements. While the valley polarization increases when tuning the Fermi level into the conduction or valence band, there is a strong decrease of the respective valley lifetime consistent with both electron-phonon and spin-orbit scattering. The longest lifetimes are seen for spin-polarized bound excitons in the band gap region. We explain our findings via two distinct, Fermi-level-dependent scattering channels of optically excited, valley-polarized bright trions either via dark or bound states. By electrostatic gating we demonstrate that the transition-metal dichalcogenide WSe2 can be tuned to be either an ideal host for long-lived localized spin states or allow for nanosecond valley lifetimes of free charge carriers (>10 ns).
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Affiliation(s)
- Manfred Ersfeld
- 2nd Institute of Physics and JARA-FIT, RWTH Aachen University, Aachen 52074, Germany
| | - Frank Volmer
- 2nd Institute of Physics and JARA-FIT, RWTH Aachen University, Aachen 52074, Germany
| | - Lars Rathmann
- 2nd Institute of Physics and JARA-FIT, RWTH Aachen University, Aachen 52074, Germany
| | - Luca Kotewitz
- 2nd Institute of Physics and JARA-FIT, RWTH Aachen University, Aachen 52074, Germany
| | - Maximilian Heithoff
- 2nd Institute of Physics and JARA-FIT, RWTH Aachen University, Aachen 52074, Germany
| | - Mark Lohmann
- Department of Physics and Astronomy, University of California, Riverside, Riverside 92521, California, United States
| | - Bowen Yang
- Department of Chemistry and Materials Science & Engineering Program, University of California, Riverside 92521, California, United States
| | - Kenji Watanabe
- National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Ludwig Bartels
- Department of Chemistry and Materials Science & Engineering Program, University of California, Riverside 92521, California, United States
| | - Jing Shi
- Department of Physics and Astronomy, University of California, Riverside, Riverside 92521, California, United States
| | - Christoph Stampfer
- 2nd Institute of Physics and JARA-FIT, RWTH Aachen University, Aachen 52074, Germany
- Peter Grünberg Institute, Forschungszentrum Jülich, Jülich 52425, Germany
| | - Bernd Beschoten
- 2nd Institute of Physics and JARA-FIT, RWTH Aachen University, Aachen 52074, Germany
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Ersfeld M, Volmer F, de Melo PMMC, de Winter R, Heithoff M, Zanolli Z, Stampfer C, Verstraete MJ, Beschoten B. Spin States Protected from Intrinsic Electron-Phonon Coupling Reaching 100 ns Lifetime at Room Temperature in MoSe 2. NANO LETTERS 2019; 19:4083-4090. [PMID: 31063385 DOI: 10.1021/acs.nanolett.9b01485] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We present time-resolved Kerr rotation measurements, showing spin lifetimes of over 100 ns at room temperature in monolayer MoSe2. These long lifetimes are accompanied by an intriguing temperature-dependence of the Kerr amplitude, which increases with temperature up to 50 K and then abruptly switches sign. Using ab initio simulations, we explain the latter behavior in terms of the intrinsic electron-phonon coupling and the activation of transitions to secondary valleys. The phonon-assisted scattering of the photoexcited electron-hole pairs prepares a valley spin polarization within the first few ps after laser excitation. The sign of the total valley magnetization, and thus the Kerr amplitude, switches as a function of temperature, as conduction and valence band states exhibit different phonon-mediated intervalley scattering rates. However, the electron-phonon scattering on the ps time scale does not provide an explanation for the long spin lifetimes. Hence, we deduce that the initial spin polarization must be transferred into spin states, which are protected from the intrinsic electron-phonon coupling, and are most likely resident charge carriers, which are not part of the itinerant valence or conduction band states.
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Affiliation(s)
- Manfred Ersfeld
- 2nd Institute of Physics and JARA-FIT , RWTH Aachen University , D-52074 Aachen , Germany
| | - Frank Volmer
- 2nd Institute of Physics and JARA-FIT , RWTH Aachen University , D-52074 Aachen , Germany
| | - Pedro Miguel M C de Melo
- nanomat/Q-mat/CESAM , Université de Liège , B-4000 Sart Tilman, Liége , Belgium
- European Theoretical Spectroscopy Facilities (ETSF)
| | - Robin de Winter
- 2nd Institute of Physics and JARA-FIT , RWTH Aachen University , D-52074 Aachen , Germany
| | - Maximilian Heithoff
- 2nd Institute of Physics and JARA-FIT , RWTH Aachen University , D-52074 Aachen , Germany
| | - Zeila Zanolli
- European Theoretical Spectroscopy Facilities (ETSF)
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB , Bellaterra, 08193 Barcelona , Spain
- Institute for Theoretical Solid State Physics , RWTH Aachen University , D-52056 Aachen , Germany
| | - Christoph Stampfer
- 2nd Institute of Physics and JARA-FIT , RWTH Aachen University , D-52074 Aachen , Germany
- Peter Grünberg Institute (PGI-9) , Forschungszentrum Jülich , D-52425 Jülich , Germany
| | - Matthieu J Verstraete
- nanomat/Q-mat/CESAM , Université de Liège , B-4000 Sart Tilman, Liége , Belgium
- European Theoretical Spectroscopy Facilities (ETSF)
| | - Bernd Beschoten
- 2nd Institute of Physics and JARA-FIT , RWTH Aachen University , D-52074 Aachen , Germany
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