First-principles study of the structural, electronic, and optical properties of Ga2O3 in its monoclinic and hexagonal phases.

International audienceThe authors report the results of a comprehensive study on the structural, electronic, and optical properties of Ga2O3 in its ambient, monoclinic (β) and high-pressure, hexagonal (α) phases in the framework of all-electron d. functional theory. In both phases, the conduction band min. is at the zone center while the valance band max. is rather flat in the k space. The calcd. electron effective mass m*e/m0 comes out to be 0.342 and 0.276 for β-Ga2O3 and α-Ga2O3, resp. The dynamic dielec. function, reflectance, and energy-loss function for both phases are reported for a wide energy range of 0-50 eV. The subtle differences in electronic and optical properties can be attributed to the higher symmetry, coordination no. of Ga atoms, and packing d. in α-Ga2O3 relative to that in β-Ga2O3. [on SciFinder(R)