Electronic interchain interactions of the Cu(1 1 0)(2 × 1)O surface––an angle-resolved photoemission study

Using angle-resolved photoemission at ℏω=21.2 eV we have measured the electronic energy band dispersion perpendicular to the Cu–O chains, i.e. along the Γ–X and Y–S directions of the surface Brillouin zone. Our work treats exclusively the occupied antibonding states observed at binding energies between EF and the upper edge of the Cu d-bands. We studied both the fully oxygen-covered surface (0.5 ML coverage) and the striped surface (global coverage <0.5 ML), where alternating Cu(1 1 0) and (2 × 1)O domains form a quasi-1D nanograting. In addition we analyze an umklapp-process of bulk substrate emission. It is induced by the (2 × 1) lattice of the adsorbate and needs to be distinguished from oxygen-derived electronic properties. We compare our results with earlier experimental studies and with available surface band structure calculations.