First principles study on the lattice thermal conductivity of α-phase Ga₂O₃

In this article, lattice thermal conductivity of α-phase Ga2O3 is investigated in a way of combining the first principles calculation and iterative solving the Boltzmann transport equation. Real-space displacement approach is employed in order to obtain both second- and third-order force constants. The effect of the microstructure on lattice thermal conductivity of α-phase Ga2O3 has been extensively studied and widely discussed. The results indicate that α-phase Ga2O3 exhibit a lower thermal conductivity compared with β-phase Ga2O3 in a temperature range from 30 to 800 K. At room temperature, 300 K, the calculated thermal conductivities of α-phase Ga2O3 are 11.61, 9.38, and 8.94 Wm−1 K−1 in the directions [100], [010], and [001], respectively. The lower thermal conductivity of α-phase Ga2O3 can be attributed to the mass difference and bond strength between Ga and O atoms. As for the phonon transport analysis, it is related to the three phonon scattering mechanism. Compared with β-phase Ga2O3, α-phase Ga2O3 exhibits a higher anharmonic phonon scattering rate. Our study aims to help to understand the thermal transport mechanism of α-phase Ga2O3 material and provide useful guidance for the future device applications and enrich the existing state of the art.