Yu-Shiba-Rusinov bound states induced by a spin flipper in the vicinity of a s-wave superconductor

TL;DR

This paper theoretically investigates Yu-Shiba-Rusinov bound states near a superconductor, revealing how a spin flipper influences zero-energy conductance peaks, which are non-topological in origin.

Contribution

It introduces a BTK approach to analyze the effect of a spin flipper on Yu-Shiba-Rusinov states and characterizes the zero-energy conductance features.

Findings

Zero-energy conductance peak forms due to spin flip

Peak is nearly quantized at 2e^2/h

Peak arises from non-topological mechanisms

Abstract

We theoretically study the formation and characteristics of Yu-Shiba-Rusinov bound states within the superconducting gap using a BTK approach in presence of a spin flipper (high spin magnetic impurity). We focus on the zero energy in the conductance spectra and show how a peak is formed at $E=0$ due to the flipping of the magnetic impurity spin but for no flip case a dip forms at $E=0$ in the conductance spectra. This $E=0$ conductance peak is almost quantized at $2e^2/h$ values, however, it arises due to non-topological reasons in contrast to the $E=0$ peak formed due to Majorana states.