VALENCE-BAND OFFSETS AND FORMATION ENTHALPY OF RECONSTRUCTED GAAS/GE(001) INTERFACES

The GaAs/Ge(001) superlattice interfaces are believed to reconstruct in order to eliminate long-range electric fields. In the simplest reconstruction both the interfacial planes are GaGe or both are AsGe. We calculate valence-band offsets of 737 and 263 meV and formation enthalpies of 352 and 357 meV per pair of interfacial atoms, respectively, for the two cases. The enthalpy of these interfaces is shown to be nearly identical to that of the nonpolar (110) interface and much larger than that of the polar (111) interface which is shown to be stable against reconstruction. © 1990 The American Physical Society.