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Exciton-Phonon Interaction and Relaxation Times from First Principles

Chen, Hsiao-Yi and Sangalli, Davide and Bernardi, Marco (2020) Exciton-Phonon Interaction and Relaxation Times from First Principles. Physical Review Letters, 125 (10). Art. No. 107401. ISSN 0031-9007. doi:10.1103/PhysRevLett.125.107401.

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Electron-phonon interactions are key to understanding the dynamics of electrons in materials and can be modeled accurately from first principles. However, when electrons and holes form Coulomb-bound states (excitons), quantifying their interactions and scattering processes with phonons remains an open challenge. Here we show a rigorous approach for computing exciton-phonon (ex-ph) interactions and the associated exciton dynamical processes from first principles. Starting from the ab initio Bethe-Salpeter equation, we derive expressions for the ex-ph matrix elements and relaxation times. We apply our method to bulk hexagonal boron nitride, for which we map the ex-ph relaxation times as a function of exciton momentum and energy, analyze the temperature and phonon-mode dependence of the ex-ph scattering processes, and accurately predict the phonon-assisted photoluminescence. The approach introduced in this work is general and provides a framework for investigating exciton dynamics in a wide range of materials.

Item Type:Article
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URLURL TypeDescription Paper
Chen, Hsiao-Yi0000-0003-1962-5767
Sangalli, Davide0000-0002-4268-9454
Bernardi, Marco0000-0001-7289-9666
Additional Information:© 2020 American Physical Society. Received 25 February 2020; accepted 31 July 2020; published 31 August 2020. We thank F. Paleari and A. Marini for a critical reading of the manuscript. This work was supported by the Department of Energy under Grant No. DE-SC0019166, which provided for theory and method development. The code development was supported by the National Science Foundation under Grant No. ACI-1642443. H.-Y. C. was partially supported by the J. Yang Fellowship at Caltech. D. S. acknowledges funding from MIUR PRIN Grant No. 20173B72NB and by the European Union’s Horizon 2020 research and innovation program (Grants No. 824143 and No. 654360). This research used resources of the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the US Department of Energy under Contract No. DE-AC02-05CH11231.
Funding AgencyGrant Number
Department of Energy (DOE)DE-SC0019166
Ministero dell'Istruzione, dell'Universita e della Ricerca (MIUR)20173B72NB
European Research Council (ERC)824143
European Research Council (ERC)654360
Department of Energy (DOE)DE-AC02-05CH11231
Issue or Number:10
Record Number:CaltechAUTHORS:20200427-081647714
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:102782
Deposited By: Tony Diaz
Deposited On:27 Apr 2020 17:14
Last Modified:16 Nov 2021 18:15

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