Effect of substitutional defects on the thermal conductivity of boron arsenide

Cubic boron arsenide (BAs) has recently been confirmed as having unconventional ultrahigh thermal conductivity, k, [1-3], which is particularly sensitive to the presence of vacancy defects [4]. Here, using density functional theory based first principles methods, we calculate the effect of various defects on the lattice thermal conductivity of BAs. We treat the phonon-defect scattering using both the Born approximation and the infinite-order T-matrix method and assess the difference between the results from these two approaches. The phonon-defect scattering rates are combined with the three-phonon and four-phonon scattering rates to obtain a full solution of the phonon Boltzmann transport equation. The calculated thermal conductivities are compared with the most recent experimental measurements.

[1] Joon Sang Kang, et. al., Science, 361, 575 ( 2018).
[2] Sheng Li et al., Science 361, 579 (2018).
[3] Fei Tian et. al., Science, 361, 582 ( 2018).
[4] Nakib Haider Protik et al., Phys. Rev. B 94, 045207 (2016).