High-resolution angle-resolved photoemission from Cu(610)

Cu(610) has a mean terrace width of six atoms. Although the regular arrangement of steps was verified by SPALEED, no step-induced surface umklapp process could be identified in UPS spectra taken with HeI radiation. This fact allows an easy comparison with results from Cu(100). In particular, we demonstrate that the final state wave vector can be determined by triangulation using exclusively the Cu(610) surface, since equivalent k-space points contribute at different electron emission angles. However, spectra from equivalent points exhibit differences in the UPS linewidth and this gives additional information on the final state lifetime. Finally we discuss the modification of a Tamm state [its analogue is observed at on the (100) surface] due to confinement by the steps.