First-principle investigation of the (001) surface reconstructions of GaSb and InSb semiconductors

The atomic and electronic structures of reconstructions with (2 $\times$ 4), (4 $\times$ 2), $c$(4 $\times$ 4) and (4 $\times$ 3) symmetry on the (001) surface of GaSb and InSb semiconductors were studied by the projector augmented-wave method. It was shown that in the cation-rich limit the $\beta$2(2 $\times$ 4) reconstruction is stable on the GaSb(001) surface, whereas $\alpha$2(2 $\times$ 4) has the lowest energy in the case of InSb. The $c$(4 $\times$ 4) reconstruction with three Sb dimers is found to be stable in the Sb-rich limit. Near stoichiometric composition the $\alpha$(4 $\times$ 3) and $\beta$(4 $\times$ 3) structures are stable that is in agreement with experimental data. Electronic structure of the (4 $\times$ 3) reconstructions with lowest surface energy is discussed. A weak influence of chemical composition of cations on the surface state structure and their localization at the formation of (4 $\times$ 3) structures was revealed. The correlation between the surface energy of some (4 $\times$ 2) and (2 $\times$ 4) reconstructions and the difference in the atomic radii of anions and cations was established.