Unoccupied surface states on clean and oxygen-covered Cu(110) and Cu(111)

Abstract

The experimentally observed surface states of the adsorbate systems Cu(110)p(2\ifmmode\times\else\texttimes\fi{}1)O and Cu(111)/${\mathrm{O}}_{2}$ can be simulated by a simple model using a planar-averaged surface barrier. The E(${k}_{?}$) dispersion curves of the adsorbate case are obtained from those of the clean-surface case by a systematic downward shift in energy which is achieved, in this particular model, by an outward movement of the barrier by 1--2 a.u.