Crystal-induced and image-potential-induced empty surface states on Cu(111) and Cu(001)

Abstract

Empty surface states of both the crystal-induced and image-potential-induced kinds have been observed on Cu(111) using k-resolved inverse photoemission. Measurements were performed at \ensuremath{\Elzxh}\ensuremath{\omega}=10.2 and 11.0 eV using a novel refracting monochromator. A simplified application of multiple-reflection theory explains the binding energies, establishes the relationship between the two kinds of state, and shows how these depend on crystal face.