Intrinsic localized surface states in GaAs

Abstract
Surface states at the cleavage plane of GaAs with energy in the band gap of the bulk band structure and with wave vector corresponding to the point γ at the centre of the [110] surface Brillouin zone are calculated using the empirical pseudopotential method, K · p theory, and the method of matching wavefunctions. The results differ markedly from those previously reported for GaAs in that, when the matching plane is situated midway between two atomic layers, not one but two localized surface states are found. When the matching plane is displaced from the central position, however, one of these localized states disappears from the band gap.