HUGE ELECTRIC-FIELDS IN GE/GAAS (001) AND (111) SUPERLATTICES AND THEIR EFFECT ON INTERFACIAL STABILITY

Self-consistent relativistic pseudopotential calculations of Ge6/(GaAs)3 (001) and (111) superlattices yield a sawtooth potential resulting in electric fields of magnitude 109 V/m. This has little effect on the (111) energy bands but localized states on the two (001) interfaces are shifted in opposite directions, resulting in a negative energy gap. Formation-enthalpy calculations indicate the (111) interface is probably stable against reconstruction while the (001) interface is probably unstable. © 1990 The American Physical Society.