One-dimensional image state on stepped Cu(100)

A one-dimensional, step-induced image state is found at vicinal Cu(100) surfaces with inverse photoemission and two-photon photoemission. Its energy nearly coincides with the bottom of the two-dimensional image-state band of the flat surface. The one-dimensional nature of the step state manifests itself in a lack of dispersion perpendicular to the steps. Parallel to the steps it exhibits free-electron-like dispersion, making this type of state an ideal model for one-dimensional electron physics. © 1994 The American Physical Society.