First-principles study of the impact of the atomic configuration on the electronic properties of AlxGa1−xN alloys

We employ first-principles calculations in the formalism of standard and hybrid density functional theory to study the electronic and structural properties of wurtzite ${\text{Al}}_{x}{\text{Ga}}_{1\ensuremath{-}x}\text{N}$ alloys. We address the discrepancies observed in literature regarding essential electronic properties of these alloys and we investigate the dependence of these properties on the atomic ordering and composition. We show that the bowing parameter is significantly affected by the atomic ordering, ranging from zero to strong downward bowing. The effects of atomic ordering of the alloys on their band offset with respect to the pure phases are also investigated. Finally, using the effective band structure approach, we study the electronic band structure of the random alloys.