Theoretical study of electron confinement in Cu corrals on a Cu(111) surface

Abstract

We present a theoretical study of the energies, lifetimes, wave functions, and decay paths of the excited electronic states in corral structures formed by Cu adatoms on the Cu(111) surface. Three different corrals with 35, 48, and 70 Cu adatoms have been studied within a joint approach including the density functional theory and wave packet propagation. Confinement of the electronic surface state inside the corral structure leads to the formation of well-defined resonances in the density of electronic states. Particular emphasis is given in the present work to the role of excited electronic states localized on the ring of Cu adatoms forming the corral. While never discussed in the past for corral structures, these states are equivalent to the one-dimensional $sp$ band of Cu atomic chains assembled on the Cu(111) surface that has been recently studied thoroughly. The coupling between the confined surface state resonances and the $sp$ state localized on the Cu ring have been studied in detail. It is shown that the $sp$ state localized on the corral wall appears as a strong perturbation in the spectrum of confined states.