Abstract
Two-photon spectroscopy is an important tool for detection of states that are dark in single-photon spectra. We calculate two-photon absorption spectra for monolayer transition-metal dichalcogenides including excitonic effects based on a Bethe-Salpeter equation approach. Both spin-orbit coupling and trigonal warping are included. Our results reveal that otherwise dark p states dominate the two-photon response. However, weakly allowed two-photon transitions coinciding with single-photon s-state resonances appear due to trigonal warping. The angular momentum character of participating excitons is analyzed and we study the sensitivity to screening by dielectric surroundings and discuss the free-carrier limit. Biexciton contributions to the high-energy two-photon response are estimated using a simplified Wannier approach. Finally, a brief comparison with recent experiments is given.
Originalsprog | Engelsk |
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Artikelnummer | 085431 |
Tidsskrift | Physical Review B |
Vol/bind | 104 |
Udgave nummer | 8 |
ISSN | 2469-9950 |
DOI | |
Status | Udgivet - 15 aug. 2021 |
Bibliografisk note
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