Ga- and As-terminated GaAs(100) surfaces are studied through first-principles density-functional pseudopotential calculations of the energies of surfaces with different stoichiometries and reconstructions. We predict structural transitions as a function of Ga and As chemical potentials within an experimentally accessible range which is shown to be fixed by the bulk energies of Ga, As, and GaAs. The bulk energies are determined accurately by the ab initio calculations. The predicted surface stoichiometries are in good agreement with experimental data.

• Received 10 November 1987

DOI:https://doi.org/10.1103/PhysRevLett.60.1962