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

TL;DR

This paper presents a theoretical study of ultrafast exciton dynamics in 2D materials under laser pulses, using advanced ab initio methods to incorporate many-body effects and electron-hole interactions.

Contribution

It introduces a combined ab initio and numerical approach to model real-time exciton dynamics in 2D materials with many-body effects included.

Findings

Many-body effects significantly influence ultrafast excitonic processes.

The approach accurately captures exciton formation under ultrashort laser excitation.

Results provide insights for optoelectronic applications of 2D materials.

Abstract

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 ab initio approach to study exciton dynamics with a highly precise numerical scheme. We incorporate electron-hole interactions through a non-local self-energy operator derived from the many-body perturbation theory (MBPT) within the time-dependent adiabatic $GW$ (TD-a$GW$) approximation. We implement this approach using the full-electron LAPW+lo method in the all-electron exciting 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.