Electronic structure of InP/Ga0.47In0.53As interfaces

The electronic structure of lattice-matched InP/${\mathrm{Ga}}_{0.47}$ ${\mathrm{In}}_{0.53}$As heterojunctions has been studied for the three main crystallographic orientations (001), (110), and (111), using state-of-the-art local-density techniques, and treating the ${\mathrm{Ga}}_x{\mathrm{In}}_{1-x}\mathrm{As}$ alloy by the virtual-crystal approximation. The valence-band offset does not depend on the crystallographic orientation within our numerical accuracy (≅ 10 meV). Our results and, in particular, the orientation independence of the band offset are examined within a linear-response approach in which the interface is treated as a perturbation with respect to an average, periodic crystal. This approach also allows us to describe in a physically sound and quantitatively accurate way the effects of interfacial strain. The effects of disorder-induced and electron-correlation-induced self-energies are also briefly discussed.