Charge transport in BAs and the role of two-phonon scattering

Abstract

The semiconductor BAs has drawn significant interest due to experimental reports of simultaneous high thermal conductivity and ambipolar charge mobility. The ab initio prediction of high electron and hole mobility assumed the dominance of charge carrier scattering by one phonon. Recently, higher-order electron-phonon scattering processes in polar and nonpolar semiconductors have been reported to have a non-negligible impact on charge transport properties, suggesting they may play a role in BAs as well. Here, we report an ab initio study of two-phonon electron and hole scattering processes in BAs. We find that inclusion of these higher-order processes reduces the computed room-temperature electron and hole mobility in BAs by around 40% from the one-phonon value, resulting in an underestimate of experimental values by a similar percentage. We suggest an experimental approach to test these predictions using luminescence spectroscopy that is applicable to the defective samples which are presently available.

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