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arXiv · 2204.02125

Dynamic screening of quasiparticles in WS$_2$ monolayers

Stefano Calati·Qiuyang Li·Xiaoyang Zhu·Julia Stähler
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Abstract

We unravel the influence of quasiparticle screening in the non-equilibrium exciton dynamics of monolayer WS$_2$. 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 WS$_2$ upon photoexcitation, but also demonstrates that exciton and carrier contributions to dynamic screening of the Coulomb interaction differ significantly.

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Stefano Calati, Qiuyang Li, Xiaoyang Zhu, Julia Stähler. 2023-01-26. Dynamic screening of quasiparticles in WS$_2$ monolayers. https://doi.org/10.1103/physrevb.107.115404

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