An atomistic model was presented, based upon scanning tunnelling microscopic results and tight-binding calculations, in order to explain an observed disorder on (001)-(2 x 4) surfaces that had been grown by means of molecular beam epitaxy. Calculations showed that the occupation, by As, of vacant Ga sites in the missing-dimer trenches of the (2 x 4) unit cell was responsible for a surface disorder in the form of kinks in the dimer rows. The disordered surface was energetically favorable at additional As coverages of up to 0.25 of a monolayer.

A.R.Avery, C.M.Goringe, D.M.Holmes, J.L.Sudijono, T.S.Jones: Physical Review Letters, 1996, 76[18], 3344-7