Circular dichroism in photoemission as a fingerprint of surface band structure: The case of ZnSe(001)-c(2x2)

Measurements of circular dichroism in the angular dependence (CDAD) of photoemission from core levels and valence bands of the ZnSe(001)-c(2x2) surface are presented. Due to the lowering of the surface symmetry compared to the bulk, the CDAD of surface-related spectral components and of bulk components exhibit different polar variations. We propose a way to identify experimentally surface-related bands in the valence-band photoemission spectra based on these symmetry considerations.