Effects of electron-electron interactions in the Yu-Shiba-Rusinov lattice model

TL;DR

This study investigates how electron-electron interactions influence the topological phases and energy gaps in a Yu-Shiba-Rusinov lattice model, revealing complex effects on phase transitions and gap distributions.

Contribution

It provides a mean-field analysis of electron-electron interactions in the Yu-Shiba-Rusinov lattice, highlighting their impact on topological properties and gap statistics.

Findings

Interactions can enhance or reduce topological gaps.

Interactions do not significantly change the distribution of Chern numbers.

Interactions increase the probability of large topological gaps in the energy distribution tails.

Abstract

In two-dimensional superconductors, Yu-Shiba-Rusinov bound states, induced by the magnetic impurities, extend over long distances giving rise to a long-range hopping model supporting a large number of topological phases with distinct Chern numbers. Here, we study how the electron-electron interactions affect on a mean-field level the selection of the realized Chern numbers and the magnitudes of the topological energy gaps in this model. We find that in the case of an individual choice of the model parameters the interactions can enhance or reduce the topological gap as well as cause topological phase transitions because of the complex interplay of superconductivity, magnetism, and large spatial extent of the Yu-Shiba-Rusinov states. By sampling a large number of realizations of Yu-Shiba-Rusinov lattice models with different model parameters, we show that statistically the interactions have no effect on the realized Chern numbers and typical magnitudes of the topological gaps. However, the interactions substantially increase the likelihood of the largest topological gaps in the tails of the energy gap distribution in comparison to the non-interacting case.