Electron-Energy-Band Determination by Photoemission from Overlayer States

Abstract

Discrete valence electron states are formed in adsorbed multilayers of Cs atoms on Cu(111) at energies within the Cu conduction-band gap at the $L$ point of the Brillouin zone. We measure the energies of these states by photoemission and obtain the wave vectors from the phase conditions satisfied by the states, and thereby determine the dispersion $E(k)$ in the perpendicular direction for part of the filled Cs valence band.