Real-time <i>GW</i>-BSE investigations on spin-valley exciton dynamics in monolayer transition metal dichalcogenide.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 33674319.
- Also identified by DOI 10.1126/sciadv.abf3759 and PMC identifier 7935363.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
We develop an ab initio nonadiabatic molecular dynamics (NAMD) method based on <i>GW</i> plus real-time Bethe-Salpeter equation (<i>GW</i> + rtBSE-NAMD) for the spin-resolved exciton dynamics. From investigations on MoS<sub>2</sub>, we provide a comprehensive picture of spin-valley exciton dynamics where the electron-phonon (e-ph) scattering, spin-orbit interaction (SOI), and electron-hole (e-h) interactions come into play collectively. In particular, we provide a direct evidence that e-h exchange interaction plays a dominant role in the fast valley depolarization within a few picoseconds, which is in excellent agreement with experiments. Moreover, there are bright-to-dark exciton transitions induced by e-ph scattering and SOI. Our study proves that e-h many-body effects are essential to understand the spin-valley exciton dynamics in transition metal dichalcogenides and the newly developed <i>GW</i> + rtBSE-NAMD method provides a powerful tool for exciton dynamics in extended systems with time, space, momentum, energy, and spin resolution.