Variable stoichiometry surface reconstructions: New models for GaAs(111) (2×2) and (19×19)

The (1» 1» 1») surface of GaAs exhibits three stable reconstructions. Two are (2×2), As stabilized and Ga stabilized respectively, and the third is (19 × 19). Transitions between these structures are obtained by variation of the experimental conditions. We propose new models for all of the above reconstructions, based on ab initio total-energy calculations and experimental information regarding surface composition. © 1986 The American Physical Society.