Role of elastic scattering in electron dynamics at ordered alkali overlayers on Cu(111)

TL;DR

This study investigates electron dynamics in alkali overlayers on Cu(111), revealing that elastic scattering from zone back folding significantly influences quantum well state line widths, alongside electron-phonon interactions.

Contribution

It demonstrates the importance of elastic scattering due to Brillouin zone back folding in ordered structures, a mechanism often overlooked in electron dynamics studies.

Findings

50% of line widths are due to electron-phonon scattering

Inelastic electron-electron scattering is negligible

Elastic scattering from zone back folding contributes significantly to line widths

Abstract

Scanning tunneling spectroscopy of p(2x2) Cs and Na ordered overlayers on Cu(111) reveals similar line widths of quasi two-dimensional quantum well states despite largely different binding energies. Detailed calculations show that 50% of the line widths are due to electron-phonon scattering while inelastic electron-electron scattering is negligible. A frequently ignored mechanism for ordered structures, i.e., enhanced elastic scattering due to Brillouin zone back folding, contributes the remaining width.