The results of first-principles total-energy calculations were reported. The atomic and electronic structure and the formation energy of the Ga-rich GaAs(001)-β2(4  x 2) surface was compared with results for the As-rich GaAs(001)-(2 x 4) surface reconstructions. The relaxed β2(4 x 2) structure was characterized by an appreciable decrease of the distance between the first and second atomic layer and gives rise to unoccupied Ga-dimer-derived surface states in the upper half of the GaAs bulk band gap. Its stability was limited to extreme Ga-rich conditions. For the InP(001) surface, a series of (4 x 2) and (2 x 4) reconstructions was investigated that was suggested to explain experimental results. Among these models, a structure containing three- and four-fold coordinated In atoms was energetically favourable, regardless of the chemical potentials of the surface constituents.

(4 x 2) and (2 x 4) Reconstructions of GaAs and InP(001) Surfaces. W.G.Schmidt: Applied Physics A, 1997, 65, 581–6