Orbital Picture of Yu-Shiba-Rusinov Multiplets

TL;DR

This study explores how single Mn atoms on superconducting lead surfaces induce Yu-Shiba-Rusinov states, revealing their dependence on adsorption sites and crystal field effects, and identifying their coupling to lead's Fermi surface.

Contribution

It provides new insights into the atomic-scale nature of YSR states and their relation to the local electronic environment and crystal field splitting.

Findings

YSR states vary with adsorption site and surface orientation.

YSR states inherit properties from Mn d-levels split by crystal field.

Long-range YSR oscillations reveal coupling to the Fermi surface.

Abstract

We investigate the nature of Yu-Shiba-Rusinov (YSR) subgap states induced by single Manganese (Mn) atoms adsorbed on different surface orientations of superconducting lead (Pb). Depending on the adsorption site, we detect a distinct number and characteristic patterns of YSR states around the Mn atoms. We suggest that the YSR states inherit their properties from the Mn $d$-levels, which are split by the surrounding crystal field. The periodicity of the long-range YSR oscillations allows us to identify a dominant coupling of the d-states to the outer Fermi sheet of the two-band superconductor Pb.