Reconstruction of the GaAs (311)A surface was studied using reflection high-energy electron diffraction and scanning tunnelling microscopy. The surface observed in situ with reflection high-energy electron-diffraction during molecular-beam epitaxy was distinguished by a lateral periodicity of 3.2nm perpendicular to the [2¯33] direction. This periodicity was confirmed by using in situ scanning tunnelling microscopy. High-resolution scanning tunnelling microscopy images furthermore reveal a surface reconstruction characterized by a dimerization of the surface As atoms. It was shown how the reconstruction could be formed, applying a simple electron-counting model. The excellent agreement with the experimental results further support this model, which was already found to explain the reconstructions of the (100) and the (111) surfaces. In order to form a semiconducting surface, the 3 upper-most layers were involved in the reconstruction process, giving rise to a depth modulation of 0.34nm.

Reconstruction of the GaAs (311)A Surface. M.Wassermeier, J.Sudijono, M.D.Johnson, K.T.Leung, B.G.Orr, L.Däweritz, K.Ploog: Physical Review B, 1995, 51, 14721-4