First-principles ultrafast exciton dynamics and time-domain spectroscopies: Dark-exciton mediated valley depolarization in monolayer WSe_{2}
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,...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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American Physical Society
2022-12-01
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| Series: | Physical Review Research |
| Online Access: | http://doi.org/10.1103/PhysRevResearch.4.043203 |
| _version_ | 1827285318351454208 |
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| author | Hsiao-Yi Chen Davide Sangalli Marco Bernardi |
| author_facet | Hsiao-Yi Chen Davide Sangalli Marco Bernardi |
| author_sort | Hsiao-Yi Chen |
| collection | DOAJ |
| description | 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 WSe_{2}, 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. |
| first_indexed | 2024-04-24T10:12:58Z |
| format | Article |
| id | doaj.art-79e940b4fd3847859b317d160535cf0f |
| institution | Directory Open Access Journal |
| issn | 2643-1564 |
| language | English |
| last_indexed | 2024-04-24T10:12:58Z |
| publishDate | 2022-12-01 |
| publisher | American Physical Society |
| record_format | Article |
| series | Physical Review Research |
| spelling | doaj.art-79e940b4fd3847859b317d160535cf0f2024-04-12T17:27:10ZengAmerican Physical SocietyPhysical Review Research2643-15642022-12-014404320310.1103/PhysRevResearch.4.043203First-principles ultrafast exciton dynamics and time-domain spectroscopies: Dark-exciton mediated valley depolarization in monolayer WSe_{2}Hsiao-Yi ChenDavide SangalliMarco BernardiCalculations 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 WSe_{2}, 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.http://doi.org/10.1103/PhysRevResearch.4.043203 |
| spellingShingle | Hsiao-Yi Chen Davide Sangalli Marco Bernardi First-principles ultrafast exciton dynamics and time-domain spectroscopies: Dark-exciton mediated valley depolarization in monolayer WSe_{2} Physical Review Research |
| title | First-principles ultrafast exciton dynamics and time-domain spectroscopies: Dark-exciton mediated valley depolarization in monolayer WSe_{2} |
| title_full | First-principles ultrafast exciton dynamics and time-domain spectroscopies: Dark-exciton mediated valley depolarization in monolayer WSe_{2} |
| title_fullStr | First-principles ultrafast exciton dynamics and time-domain spectroscopies: Dark-exciton mediated valley depolarization in monolayer WSe_{2} |
| title_full_unstemmed | First-principles ultrafast exciton dynamics and time-domain spectroscopies: Dark-exciton mediated valley depolarization in monolayer WSe_{2} |
| title_short | First-principles ultrafast exciton dynamics and time-domain spectroscopies: Dark-exciton mediated valley depolarization in monolayer WSe_{2} |
| title_sort | first principles ultrafast exciton dynamics and time domain spectroscopies dark exciton mediated valley depolarization in monolayer wse 2 |
| url | http://doi.org/10.1103/PhysRevResearch.4.043203 |
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