# Thermally-Enhanced Fr\"ohlich Coupling in SnSe

## TL;DR

This study investigates how thermal effects enhance the Fr"ohlich electron-phonon coupling in SnSe, revealing mechanisms that influence its electronic and transport properties relevant for thermoelectric applications.

## Contribution

It introduces ab-initio calculations showing thermal enhancement of Fr"ohlich coupling in SnSe, linking lattice dynamics to transport properties at finite temperature.

## Key findings

- Thermal lattice dynamics induce large Fr"ohlich interaction enhancement.
- Ab-initio calculations match experimental photoemission and conductivity data.
- Interplay between thermal expansion and electron-phonon coupling affects transport.

## Abstract

To gain insight into the peculiar temperature dependence of the thermoelectric material SnSe, we employ many-body perturbation theory and explore the influence of the electron-phonon interaction on its electronic and transport properties. We show that a lattice dynamics characterized by soft highly-polar phonons induces a large thermal enhancement of the Fr\"ohlich interaction. We account for these phenomena in ab-initio calculations of the photoemission spectrum and electrical conductivity at finite temperature, unraveling the mechanisms behind recent experimental data. Our results reveal a complex interplay between lattice thermal expansion and Fr\"ohlich coupling, providing a new rationale for the in-silico prediction of transport coefficients of high-performance thermoelectrics.