Study of Surface States on Cu(110) Using Optical Reflectance Anisotropy

We report spectroscopic measurements of the azimuthal anisotropy in the normal incidence reflectivity of a clean and adsorbate-covered single-crystal metal surface: Reflectance anisotropy spectra were taken between 1.5 and 6 eV from Cu(110). On the clean surface, a sharp resonance is found which is assigned to a transition between two surface states at the Ȳ point of the surface Brillouin zone. The resonance can be removed by adsorption, and its energetic position is in good agreement with photoemission and inverse photoemission work.