LATERAL CONFINEMENT OF SURFACE-STATES ON STEPPED CU(111)

By means of scanning tunneling microscopy we observe the lateral confi nement of the two-dimensional electron gas of a s,p-like surface state by a regular distribution of steps on vicinal Cu(111). The surface st ate appears with a reduced binding energy as a result of scattering at steps and partial confinement within the terraces, as revealed by loc al scanning tunneling spectroscopy. The energy shift of the bottom of the surface state band is measured for several vicinal Cu surfaces wit h angle-resolved photoemission and found to be consistent with a simpl e one-dimensional Kronig-Penney model.