First principles study on the lattice thermal conductivity of α-phase Ga 2 O 3

Gang Yang (1) , Pedro Rojo Romeo (2) , Aleksandra Apostoluk (1) , Bertrand Vilquin (3, 1)

1 INL - MFN - INL - Matériaux Fonctionnels et Nanostructures
2 INL - Institut des Nanotechnologies de Lyon
3 ECL - École Centrale de Lyon

In this article, lattice thermal conductivity of α-phase Ga 2 O 3 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 Ga 2 O 3 has been extensively studied and widely discussed. The results indicate that α-phase Ga 2 O 3 exhibit a lower thermal conductivity compared with β-phase Ga 2 O 3 in a temperature range from 30 to 800 K. At room temperature, 300 K, the calculated thermal conductivities of α-phase Ga 2 O 3 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 Ga 2 O 3 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 Ga 2 O 3 , α-phase Ga 2 O 3 exhibits a higher anharmonic phonon scattering rate. Our study aims to help to understand the thermal transport mechanism of α-phase Ga 2 O 3 material and provide useful guidance for the future device applications and enrich the existing state of the art.

Domaines: Science des matériaux [cond-mat.mtrl-sci]; Micro et nanotechnologies/Microélectronique

Gang Yang, Pedro Rojo Romeo, Aleksandra Apostoluk, Bertrand Vilquin. First principles study on the lattice thermal conductivity of α-phase Ga 2 O 3. Journal of Vacuum Science & Technology A, 2022, 40 (5), pp.052801. ⟨10.1116/6.0001870⟩. ⟨hal-03735982⟩