Theoretical study of the cinnabar phases in GaAs and GaP

Abstract
We present an ab initio pseudopotential study of the cinnabar phases of GaAs and GaP, which are covalently bonded fourfold-coordinated structures formed from twisted tetrahedra. We find that these phases are not thermodynamically stable. We suggest, however, that cinnabar-GaP could be formed as a metastable phase by releasing pressure from the Cmcm phase, as recently observed in GaAs.