The relative stability of ideal-geometry versus intermixed buried semiconductor interfaces was studied by using first-principles density functional methods. It was found that, although intermixing of an ideal lattice-matched GaAs/AlAs(001) interface required energy, intermixing was an energy-lowering process at the coherent strained-layer (001) interfaces of lattice-mismatched materials. Intermixing of an ideal strained-layer (001) interface lowered the energy mainly because it partially relieved the strain in a local region near to the interface. It was predicted that lattice-mismatched interfaces would have a greater degree of atomic-scale micro-roughness than would the analogous interfaces of lattice-matched materials.

R.G.Dandrea, C.B.Duke: Physical Review B, 1992, 45[24), 14065-8