The nature of highly anisotropic free-electron-like states in a glycinate monolayer on Cu(100)

TL;DR

This study reveals that a highly anisotropic free-electron-like state in a glycinate monolayer on Cu(100) originates from a Cu Shockley surface state, with glycinate ions significantly enhancing tunneling into this state.

Contribution

It demonstrates from density functional theory that the observed free-electron-like state is due to a Cu Shockley surface state affected by glycinate ions.

Findings

The free-electron-like state is from a Cu Shockley surface state.

Glycinate ions enhance tunneling into this surface state.

The state exhibits highly anisotropic dispersion.

Abstract

The free-electron-like state observed in a scanning tunneling spectroscopy study of a chiral p(2x4) monolayer of glycinate ions on the Cu(100) surface [K. Kanazawa et al, J. Am. Chem. Soc. 129, 740 (2007)] is shown from density functional theory calculations to originate from a Cu Shockley surface state at the surface Brillouin zone boundary of the clean surface with highly anisotropic dispersion. The presence of the glycinate ions on the surface causes a dramatically enhanced tunneling into this surface state that is otherwise not observed in tunneling on the bare surface.