Unoccupied surface states in Cu(001)

Abstract

The energy versus momentum dispersion of empty electronic states in Cu(001) has been measured with $\overrightarrow{\mathrm{k}}$-resolved inverse photoemission. Four different final bands are identified. Theoretical calculations employing the one-step model of inverse photoemission prove that two of the four emission branches are due to bulk direct transitions while the remaining two are due to surface states of the Shockley and Tamm kinds, respectively.