Phonon-induced exciton weak localization in two-dimensional semiconductors

We theoretically study the contribution of quantum effects to the exciton diffusion coefficient in atomically thin crystals. It is related to the weak localization caused by the interference of excitonic wavefunctions on the trajectories with closed loops. Due to the weak inelasticity of the exciton-phonon interaction, the effect is present even if the excitons are scattered by long-wavelength acoustic phonons. We consider exciton interaction with longitudinal acoustic phonons with linear dispersion and flexural phonons with quadratic dispersion. We identify the regimes where the weak localization effect can be particularly pronounced. We also briefly address the role of free charge carriers in the exciton quantum transport and, within the self-consistent theory of localization, the weak localization effects beyond the lowest order.

Automated summary

This study theoretically investigates the contribution of quantum effects to the exciton diffusion coefficient in atomically thin crystals. The weak localization caused by the interference of excitonic wavefunctions on closed loop trajectories plays a significant role, even when the excitons are scattered by long-wavelength acoustic phonons. The study identifies the regimes where the weak localization effect is particularly pronounced and briefly addresses the role of free charge carriers in exciton quantum transport and higher-order weak localization effects within the self-consistent theory of localization.