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

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.