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First-principles ultrafast exciton dynamics and time-domain spectroscopies: Dark-exciton mediated valley depolarization in monolayer WSe₂

Chen, Hsiao-Yi and Sangalli, Davide and Bernardi, Marco (2022) First-principles ultrafast exciton dynamics and time-domain spectroscopies: Dark-exciton mediated valley depolarization in monolayer WSe₂. Physical Review Research, 4 (4). Art. No. 043203. ISSN 2643-1564. doi:10.1103/physrevresearch.4.043203. https://resolver.caltech.edu/CaltechAUTHORS:20230118-50417000.1

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Abstract

Calculations combining first-principles electron-phonon (e-ph) interactions with the Boltzmann equation enable studies of ultrafast carrier and phonon dynamics. However, in materials with weak Coulomb screening, electrons and holes form bound excitons so their scattering processes become correlated, posing additional challenges for modeling nonequilibrium physics. Here we show calculations of ultrafast exciton dynamics and related time-domain spectroscopies using ab initio exciton-phonon (ex-ph) interactions together with an excitonic Boltzmann equation. Starting from the nonequilibrium exciton populations, we develop simulations of time-domain absorption and photoemission spectra that take into account electron-hole correlations. We use this method to study monolayer WSe₂, where our calculations predict subpicosecond timescales for exciton relaxation and valley depolarization and reveal the key role of intermediate dark excitons. The approach introduced in this paper enables a quantitative description of nonequilibrium dynamics and ultrafast spectroscopies in materials with strongly bound excitons.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1103/PhysRevResearch.4.043203DOIArticle
ORCID:
AuthorORCID
Chen, Hsiao-Yi0000-0003-1962-5767
Sangalli, Davide0000-0002-4268-9454
Bernardi, Marco0000-0001-7289-9666
Alternate Title:First-principles ultrafast exciton dynamics and time-domain spectroscopies: Dark-exciton mediated valley depolarization in monolayer WSe2
Additional Information:Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. The authors thank Ivan Maliyov and Jinsoo Park for fruitful discussions. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Advanced Scientific Computing Research and Office of Basic Energy Sciences, Scientific Discovery through Advanced Computing (SciDAC) program under Award No. DESC0022088, which supported method development. M.B. was partially supported by the Liquid Sunlight Alliance, which is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Award No. DE-SC0021266. Code development was partially funded by the National Science Foundation under Grant No. OAC-2209262. H.-Y. Chen was partially supported by the J. Yang Fellowship. D.S. acknowledges funding from Italian MIUR, PRIN BIOX Grant No. 20173B72NB, and from the EU MaX project Materials design at the eXascale H2020-INFRAEDI-2018-2020, Grant Agreement No. 824143. This research used resources of the National Energy Research Scientific Computing Center (NERSC), a U.S. Department of Energy Office of Science User Facility located at Lawrence Berkeley National Laboratory, operated under Contract No. DE-AC02-05CH11231.
Group:Liquid Sunlight Alliance
Funders:
Funding AgencyGrant Number
Department of Energy (DOE)DE-SC0022088
Department of Energy (DOE)DE-SC0021266
NSFOAC-2209262
J. Yang Family and FoundationUNSPECIFIED
Ministero dell’Istruzione, dell’Università e della Ricerca (MIUR)20173B72NB
European Research Council (ERC)824143
Department of Energy (DOE)DE-AC02-05CH11231
Issue or Number:4
DOI:10.1103/physrevresearch.4.043203
Record Number:CaltechAUTHORS:20230118-50417000.1
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20230118-50417000.1
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:118849
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:18 Jan 2023 20:03
Last Modified:07 Feb 2023 19:03

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