Exceptionally strong phonon scattering by B substitution in cubic SiC

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.

5 pages, 5 figures