# Effect of local chemistry and structure on thermal transport in doped GaAs

## TL;DR

This study uses first-principles calculations to explore how different dopant-induced DX centers in GaAs affect thermal conductivity by resonant phonon scattering linked to electronic structure and vibrational modes.

## Contribution

It reveals the microscopic mechanisms by which specific dopants alter thermal transport in GaAs, connecting electronic structure, defect formation, and phonon scattering.

## Key findings

- DX centers cause resonant phonon scattering affecting thermal conductivity.
- Lone pairs in dopants lead to asymmetric DX centers and localized vibrational modes.
- Resonant scattering is linked to flat minima in the energy landscape.

## Abstract

Using a first-principles approach, we analyze the impact of \textit{DX} centers formed by S, Se, and Te dopant atoms on the thermal conductivity of GaAs. Our results are in good agreement with experiments and unveil the physics behind the drastically different effect of each kind of defect. We establish a causal chain linking the electronic structure of the dopants to the thermal conductivity of the bulk solid, a macroscopic transport coefficient. Specifically, the presence of lone pairs leads to the formation of structurally asymmetric \textit{DX} centers that cause resonant scattering of incident phonons. The effect of such resonances is magnified when they affect the part of the spectrum most relevant for thermal transport. We show that these resonances are associated with localized vibrational modes in the perturbed phonon spectrum. Finally, we illustrate the connection between flat adjacent minima in the energy landscape and resonant phonon scattering through detailed analyses of the energy landscape of the defective structures.