Exciton renormalization and optical absorption in doped monolayer transition metal dichalcogenides
Phys. Rev. B 114, 235416 – Published 26 October, 2026
DOI: https://doi.org/10.1103/wcwj-8th7
Abstract
We develop a computationally efficient finite-temperature continuum approach for exciton renormalization and optical absorption in doped monolayer transition-metal dichalcogenides. The model combines a massive-Dirac electronic structure, the nonlocal Rytova-Keldysh interaction, finite-temperature carrier screening, Hartree-Fock (HF) and random phase approximation (RPA) quasiparticle self-energy corrections, and a momentum-space Bethe-Salpeter equation (BSE). This approach enables the quasiparticle gap, exciton transition energies, and exciton binding energies to be followed systematically as functions of carrier density, temperature, dielectric environment, material parameters, and excitonic state. We find that quasiparticle BGR and binding-energy reduction can substantially compensate, producing comparatively weak shifts of the lowest exciton resonance, while excited states show a stronger response to screening. The RPA calculations further reveal a nonmonotonic temperature dependence of the excitonic energies at low carrier densities, reflecting the competition between quasiparticle and excitonic renormalizations. The calculated optical spectra also exhibit pronounced material-dependent density and temperature trends. These results substantially advance the compensation picture, providing a unified finite-temperature framework for excitonic many-body renormalization in monolayer TMDCs.
