Structure and optical properties of the Sb-stabilized GaSb(001) surface

We suggest a model for the c(2 x 6) phase of the Sbstabilized GaSb(001) surface, whereby Sb atoms in the second layer are partially substituted by Ga. This 'doping' effect enables the surface to fulfil the electron counting rule whilst maintaining a reconstruction based on long dimer chains. Total energy calculations verify that the suggested reconstruction is relatively stable, and calculations of the reflectance anisotropy spectra confirm that it comprises a major component of the largely disordered surface.