{111} Surfaces of Compounds with Zincblende Structure

Abstract

Bulk-terminated {111}-1 × 1 surfaces of zincblende-structure compounds would be either cation- or anion-terminated. Such [111]- and [1̄1̄1̄]-oriented surfaces, respectively, are found to be 2 × 2-reconstructed. The GaAs(111)-2 × 2 structure results from the existence of Ga vacancies which expose three As atoms of the second layer. The atomic arrangement is thus similar to the Ga-As zigzag chains on cleaved (110)-1 × 1 surfaces. The GaAs(1̄1̄1̄)-2 × 2 reconstruction, on the other hand, consists of Astrimers on a complete As layer beneath. The presence of As vacancies is excluded since their formation is endothermic on such surfaces.