# Phonon wind and drag of excitons in monolayer semiconductors

## TL;DR

This paper develops a theoretical framework for understanding how non-equilibrium phonons influence exciton transport in monolayer semiconductors, revealing mechanisms like phonon wind and Seebeck effect that shape exciton distribution.

## Contribution

It introduces a novel theory of exciton-phonon interactions under non-equilibrium conditions, explaining exciton drag and halo formation in monolayer materials.

## Key findings

- Exciton drag by non-equilibrium phonons can create halo-like exciton distributions.
- Ballistic and diffusive phonon regimes both contribute to exciton transport.
- Phonon wind effects can be significant in localized excitation scenarios.

## Abstract

We study theoretically the non-equilibrium exciton transport in monolayer transition metal dichalcogenides. We consider the situation where excitons interact with non-equilibrium phonons, e.g., under the conditions of localized excitation where a ``hot spot'' in formed. We develop the theory of the exciton drag by the phonons and analyze in detail the regimes of diffusive propagation of phonons and ballistic propagation of phonons where the phonon wind is formed. We demonstrate that a halo-like spatial distribution of excitons akin observed in [Phys. Rev. Lett. 120, 207401 (2018)] can be formed as a result of the exciton drag by non-equilibrium phonons or Seebeck effect.