Step-induced one-dimensional surface state on Cu(332)

The Shockley $(L$ gap) surface state on Cu(332) has been studied by angle scanned ultraviolet photoelectron spectroscopy. The Fermi surface indicates a two-dimensional (2D) and a one-dimensional (1D) state, both propagating freely parallel to the steps. Normal to the steps, the 2D state is slightly confined while the 1D state is localized. The 1D state can be rationalized either by disorder in the one-dimensional step lattice or by surface-bulk coupling at the individual steps. In both scenarios this 1D state represents an important link between scanning tunneling microscopy/spectroscopy and photoemission data.