Surface states and charge accumulation states on reconstructed InAs(001) surfaces

Occupied electronic states at the Fermi level are found in all investigated cases. For the arsenic rich surfaces a single pocket of the states is found close to the Γ¯1×1 point in the reciprocal space while for the indium-rich surfaces multiple pockets of states are seen close to the Γ¯4×2 points, i.e., in accordance with periodicity of the surface. It is concluded that these states have a character of charge accumulation states (CAS), however, in the case of the indium-rich surface, the CAS are in resonance with surface states.