Tamm surface resonances in very low energy electron scattering from clean metal surfaces

TL;DR

This paper identifies a new Tamm-type surface resonance mechanism responsible for low-energy electron scattering features on Cu(111) surfaces, differing from traditional Shockley and Rydberg resonances, and explains observed reflectivity features systematically.

Contribution

It introduces a novel Tamm surface resonance mechanism for low-energy electron scattering on metal surfaces, expanding understanding beyond traditional resonance types.

Findings

Resonance near 19.8 eV on Cu(111) is due to scattering at the interstitial potential rise.

This mechanism explains all features in the electron reflectivity data systematically.

The Tamm resonance differs fundamentally from Shockley and Rydberg resonances.

Abstract

Very low-energy features which occur in electron reflectivities from clean fcc metal (111) surfaces have been subject to a number of interpretations. Here we analyse the feature near 19.8 eV on Cu(111) at normal incidence and find that it is due to resonant scattering at the rise of the muffin-tin average interstitial potential between atomic layers on approach to the surface from the bulk. This new mechanism corresponds to a Tamm-type surface resonance which is very different in formation to the usual Shockley and Rydberg resonances and explains all features in a systematic way.