Coupling of Yu-Shiba-Rusinov states in 1D chains of Fe atoms on Nb(110)

TL;DR

This paper investigates how Yu-Shiba-Rusinov states in Fe chains on Nb(110) hybridize, revealing energy splitting and symmetry-dependent behaviors that advance understanding of magnetic impurity interactions in superconductors.

Contribution

It provides detailed experimental insights into YSR state coupling in 1D Fe chains, highlighting energy splitting and symmetry effects with chain length dependence.

Findings

YSR peaks split into multiple states with different symmetries

Energy positions of states depend on chain length

Observation of even and odd state behaviors

Abstract

The hybridization of Yu-Shiba-Rusinov states in dimers of magnetic impurities leads to molecular-like bonding and antibonding modes. In many-impurity systems, the interaction gives rise to YSR bands and can even result in the formation of a topologically non-trivial superconducting state, characterized by Majorana fermions at the edges of the system. To obtain a more detailed understanding of these interactions, we investigate the coupling of YSR states in short one-dimensional Fe chains on clean Nb(110). We observe a splitting of the single-atom YSR peaks into multiple states with even or odd spatial symmetry and identify a peculiar dependence of the even and odd states' energy position on the chain length.