Ab initio approach for exciton-phonon interactions and exciton dynamics

Advances in ab initio calculations for electron-phonon (eph) coupling has enabled high- accurate predictions on phenomenon rooted in the interplay between carrier and lattice vibration in materials ranging from silicon semiconductors and molecular crystals to perovskites. However, in materials of weak Coulomb screening, such as low-dimensional semiconductors and quantum dots, predicting the carrier dynamics remains an open field to explore; there, carriers are dominated by strong-bounded electron-hole paired excitation, i.e., the exciton.

In this talk, we will discuss the method combining many-body perturbation theory and density functional perturbation theory to compute the exciton-phonon (ex-ph) coupling strength. Subsequently, we will present treatments to study statical observables that can predict carrier relaxation and phonon-modulated optical response. Lastly, we introduce the approaches adopting the Boltzmann transport equation to examine the ultrafast transient signatures, such as trARPES and transient absorption.