Real-time exciton dynamics in two-dimensional materials under ultrashort laser pulses

The optical response of two-dimensional materials is often significantly impacted by excitonic effects due to the reduced screening of attractive Coulomb interactions in low-dimensional systems. Accurate modeling of exciton formation and real-time dynamics is essential to understanding their ultrafast optical properties. In this study, we theoretically investigate the exciton dynamics in a two-dimensional hexagonal boron nitride (h-BN) and a germanium sulfide (GeS) monolayers exposed to an ultrashort laser pulse. We analyze the system's response to the external field in one- and two-photon excitation regimes. For our calculations, we combine a state-of-the-art approach to study exciton dynamics with a highly precise numerical scheme. We incorporate electron-hole interactions through a nonlocal self-energy operator derived from the many-body perturbation theory (MBPT) within the time-dependent adiabatic G W ( TD − a G W ) approximation. We implement this approach using the full-electron LAPW + lo method in the all-electron package. Our results elucidate the role of many-body effects in shaping ultrafast excitonic processes in two-dimensional materials, contributing to the fundamental understanding necessary for optoelectronic and photonic applications.