Significant reduction of lattice thermal conductivity by electron-phonon interaction in silicon with high carrier concentrations: a first-principles study

TL;DR

This study uses first-principles calculations to show that high carrier concentrations in silicon significantly reduce its lattice thermal conductivity through electron-phonon interactions, impacting thermoelectric material performance.

Contribution

It provides the first detailed first-principles analysis of how electron-phonon interactions affect phonon lifetimes and thermal conductivity in silicon at high carrier densities.

Findings

Thermal conductivity decreases by up to 45% at high carrier concentrations.

Electron-phonon scattering significantly impacts phonon lifetimes.

Reduction in thermal conductivity is relevant for thermoelectric applications.

Abstract

Electron-phonon interaction has been well known to create major resistance to electron transport in metals and semiconductors, whereas less studies were directed to its effect on the phonon transport, especially in semiconductors. We calculate the phonon lifetimes due to scattering with electrons (or holes), combine them with the intrinsic lifetimes due to the anharmonic phonon-phonon interaction, all from first-principles, and evaluate the effect of the electron-phonon interaction on the lattice thermal conductivity of silicon. Unexpectedly, we find a significant reduction of the lattice thermal conductivity at room temperature as the carrier concentration goes above 1e19 cm-3 (the reduction reaches up to 45% in p-type silicon at around 1e21 cm-3), a range of great technological relevance to thermoelectric materials.