QSGW calculation of the band structure of Ga2O3-Al2O3 alloys

β-Ga2O3 has recently drawn attention as an ultra-wide bandgap semiconductor. The alloys between Ga2O3 and Al2O3 are of interest to obtain even higher band gap materials. The two materials have different ground state structures, monoclinic β-Ga2O3, and corundum α-Al2O3 respectively. We study the Ga2O3-Al2O3 alloys in both the structures using the linearized muffin-tin orbital approach and ABINIT pseudopotential approach for the relaxation of the structural parameters. We consider all possible mixed structures within the common 10 atom primitive unit cells, with compositions x = 0, 0.25, 0.5, 0.75, 1.0 in (Ga2O3)1−x(Al2O3)x. We find the relative ordering of the two structures in the end compounds in agreement with experiment and energy differences in good agreement with previous computational work. We find the Al atoms tend to preferentially occupy the octahedral site when substituting for Ga. The band structure of the alloy models in the two structures is evaluated using the QSGW method.