Vacancy-Buckling Model for the (2×2) GaAs(111) Surface

Abstract

A vacancy-buckling model is proposed for the (2\ifmmode\times\else\texttimes\fi{}2) structure of the GaAs(111) surface. The model is confirmed by analysis of low-energy electron diffraction spectra. A reconstruction mechanism, basic to III-V compound surfaces, is proposed which favors equal numbers of dangling bonds on the nearest Ga and As neighbors. This model explains the (2\ifmmode\times\else\texttimes\fi{}2) and (1\ifmmode\times\else\texttimes\fi{}1) periodicities observed on (111) and (110) surfaces, respectively.