Transition from terrace to step modulation in the surface state wave function at vicinal Cu(1 1 1)

The electron wave function at Cu(1 1 1) vicinal surfaces switches between two qualitatively different regimes, i.e. from terrace modulation at small miscut angles to step modulation for large miscuts. This is deduced in angle resolved photoemission experiments from the photon energy dependent shift of the surface band. In this work we examine the critical miscut of 7° (17 Å terrace width) at which the transition is observed. The analysis of the data within a diffraction-like framework is consistent with a mixed terrace–step modulation. The mechanism that triggers the switch-over from terrace to step modulation of the surface state is discussed.