We unravel the influence of quasiparticle screening in the non-equilibrium exciton dynamics of monolayer WS2. We report pump photon energy-dependent exciton blue and red-shifts from time-resolved-reflectance contrast measurements. Based on a phenomenological model, we isolate the effective impact of excitons and free carriers on the renormalization of the quasi-free particle band gap, exciton binding energy and linewidth broadening. By this, our work does not only provide a comprehensive picture of the competing phenomena governing the exciton dynamics in WS2 upon photoexcitation, but also demonstrates that exciton and carrier contributions to dynamic screening of the Coulomb interaction differ significantly.
@article{arxiv.2204.02125,
title = {Dynamic screening of quasiparticles in WS$_2$ monolayers},
author = {Stefano Calati and Qiuyang Li and Xiaoyang Zhu and Julia Stähler},
journal= {arXiv preprint arXiv:2204.02125},
year = {2023}
}