Role of the intrinsic surface state in the decay of image states at a metal surface

TL;DR

This study investigates how the intrinsic surface state influences the decay of the first image state at Cu(111) surfaces, revealing that it accounts for about 40% of the total decay linewidth, with decay depending on momentum.

Contribution

It provides a detailed theoretical analysis of the intrinsic surface state's role in image state decay using GW approximation and realistic potential models.

Findings

Intrinsic surface state contributes ~40% to decay linewidth.

Decay rates depend on the parallel momentum of the image state.

Decay into the surface state significantly affects linewidths.

Abstract

The role of the intrinsic surface state ($n=0$) in the decay of the first image state ($n=1$) at the (111) surface of copper is investigated. Inelastic linewidths are evaluated from the knowledge of the imaginary part of the electron self-energy, which we compute, within the GW approximation of many-body theory, by going beyond a free-electron description of the metal surface. Single-particle wave functions are obtained by solving the Schr\"odinger equation with a realistic one-dimensional model potential, and departure of the motion along the surface from free-electron behaviour is considered through the introduction of the effective mass. The decay of the first image state of Cu(111) into the intrinsic surface state is found to result in a linewidth that represents a 40% of the total linewidth. The dependence of linewidths on the momentum of the image state parallel to the surface is also investigated.