Twofold symmetry in the surface electronic structure of ZnSe(0 0 1)-c(2 × 2): Theory and experiment

Surface electronic band structure of ZnSe(0 0 1)-c(2 × 2) calculated using ab initio methods is compared to angle-resolved photoemission data. The experimental photoelectron spectra clearly reveal the surface-induced breaking of the fourfold bulk symmetry. Predicted surface-related features are identified in the experimental data and their origin is determined by comparison with layer-resolved band-structure calculations.