Comparison of dipole layers, band offsets, and formation enthalpies of GaAs-AlAs(110) and (001) interfaces

We report a very careful, self-consistent, relativistic pseudopotential calculation of the interfacial dipole double-layer potential, valence-band offset, and formation enthalpy of (GaAs${)}_3$(AlAs${)}_3$(110). A comparison is made with identical calculations for the (001) superlattice with the following results [(001) in parentheses]: The interfacial dipole layer is 315 (154) meV. The formation enthalpy per twelve-atom unit cell is -21.9 (+1.7) meV. The valence-band offset is 447 (446) meV. This lends credence to the idea that the band offset is a difference of bulk quantities and that vastly different interfaces set up whatever double layer is necessary to maintain that difference.