Surface resonance transition of roughened Cu(1 1 0)

The temperature dependence of the reflection anisotropy spectroscopy (RAS) of a Cu(1 1 0) surface has been studied over the temperature range 700-1000 K. Because of the roughening transition at 900 K, the bimodal feature at 4.2 eV for a clean surface shifted to 4.3 eV on annealing. A significant decrease in intensity of the same energy level was also observed with increasing annealing temperature. In the annealing temperature range 700-1000 K, anharmonic behavior is expected to be the predominant process of atomic disordering at the surface. Changes in the RAS of Cu(1 1 0) as a result of thermal processing can be understood in terms of the associated changes in surface states. The RAS signal for a surface resonance transition at 4.2 eV is associated with monoatomic [0 0 1] steps.