Origin and temperature dependence of the surface optical anisotropy on Cu(1Â 1Â 0)

The surface optical anisotropy on Cu(1 1 0) at photon energies around 2.1 eV has been studied by reflectance difference spectroscopy (RDS). The observed anisotropy can be described as a superposition of three different contributions: optical transitions between Cu(1 1 0) surface states, interband transitions involving modified Cu bulk states and a Drude contribution due to surface intraband transitions, respectively. The thermal behaviour of the RDS signal has been investigated in the temperature range from 12 to 1000 K. The results are well reproduced by considering the temperature dependence of the surface states and the bulk d-band involved in the surface optical anisotropy.