# Exceptionally strong phonon scattering by B substitution in cubic SiC

## TL;DR

This study uses ab-initio calculations to show that boron substitution in cubic SiC causes exceptionally strong phonon scattering, significantly reducing thermal conductivity due to resonant scattering effects, contrary to classical models.

## Contribution

It reveals that B substitution in cubic SiC induces stronger phonon scattering than vacancies, challenging classical impurity scattering models with a new resonant scattering mechanism.

## Key findings

- B substitution causes stronger phonon scattering than vacancies.
- Resonant phonon scattering explains the strong effect of B in SiC.
- Classical mass-difference models underestimate B's impact.

## Abstract

We use ab-initio calculations to predict the thermal conductivity of cubic SiC with different types of defects. An excellent quantitative agreement with previous experimental measurements is found. The results unveil that B$_\mathrm{C}$ substitution has a much stronger effect than any of the other defect types in 3C-SiC, including vacancies. This finding contradicts the prediction of the classical mass-difference model of impurity scattering, according to which the effects of B$_\mathrm{C}$ and N$_\mathrm{C}$ would be similar and much smaller than that of the C vacancy. The strikingly different behavior of the B$_\mathrm{C}$ defect arises from a unique pattern of resonant phonon scattering caused by the broken structural symmetry around the B impurity.