Surface electronic structure of O(2 × 1)/Cu(1 1 0): Role of the surface state at the zone boundary -point in STS

Density functional theory calculations have been used to study the electronic structure of the O(2 × 1)/Cu(1 1 0) surface. In particular a surface state at the zone boundary Y ¯ -point of the surface Brillouin zone, that has been experimentally observed in STS spectra at an energy of + 0.56 eV, is also found in our calculations at about the same energy. The energy dependence of the local density of states shows a prominent feature, that is identified with the surface state at the Y ¯ -point, in agreement with measured dI/dV-spectra. The dI/dV-maps slightly above the surface state energy show a modulation in the [0 0 1] direction with the lattice periodicity (0.36 nm) that reflects the spatial dependence of the charge density. Our results are consistent with the assumption of an added row reconstruction of the Cu(1 1 0) surface after O adsorption.