Kondo effect of Co adatoms on Ag monolayers on noble metal surfaces

TL;DR

This study measures the Kondo temperature of Co adatoms on Ag monolayers on Cu and Au surfaces, revealing that the Kondo interaction is highly local and insensitive to surface states or bulk band edges.

Contribution

It demonstrates that the Kondo temperature for Co on Ag monolayers is similar to that on bulk Ag(111), indicating a local interaction unaffected by substrate properties.

Findings

Kondo temperature of Co on Ag monolayers matches that on bulk Ag(111).

Surface Kondo interactions are highly local and not influenced by surface states.

The Kondo energy scale is insensitive to the substrate's surface and bulk electronic properties.

Abstract

The Kondo temperature $T_K$ of single Co adatoms on monolayers of Ag on Cu and Au(111) is determined using Scanning Tunneling Spectroscopy. $T_K$ of Co on a single monolayer of Ag on either substrate is essentially the same as that of Co on a homogenous Ag(111) crystal. This gives strong evidence that the interaction of surface Kondo impurities with the substrate is very local in nature. By comparing $T_K$ found for Co on Cu, Ag, and Au (111)-surfaces we show that the energy scale of the many-electron Kondo state is insensitive to the properties of surface states and to the energetic position of the projected bulk band edges.