Interplay between topology and interactions in superconducting chains

TL;DR

This paper explores how electronic correlations and disorder influence the topological properties of a superconducting Kitaev chain by extending it with a Falicov-Kimball interaction, which remains exactly solvable under certain conditions.

Contribution

It introduces an exactly solvable correlated Kitaev chain model with disorder, enabling detailed analysis of the interplay between correlations, topology, and disorder.

Findings

Exact solutions reveal how correlations modify topological phases.

Disorder effects lead to new phenomena in topological superconductors.

The model provides insights into real systems with interactions and disorder.

Abstract

Most studies of non-trivial topological systems are carried out in non-interacting models that admit an exact solution. This raises the question, to which extent the consideration of electronic correlations and disorder, present in real systems, modify these results. Exact solutions of correlated electronic systems with non-trivial topological properties, although fundamental are scarce. Among the non-interacting soluble models, we single out the Kitaev p-wave superconducting chain. It plays a crucial role in clarifying the appearance of emergent quasi-particles, the Majorana modes, associated with non-trivial topological properties. Given the relevance of this model, it would be extremely useful if it could be extended to include correlations and still remain solvable. In this work we investigate a superconducting Kitaev chain that interacts through a Falicov-Kimball Hamiltonian with a background of localized electrons. For some relevant values of the parameters, this model can be solved exactly by mapping into a non-interacting one. This allows for a detailed study of the interplay between electronic correlations and non-trivial topological behavior. Besides, the random occupation of the chain by the local moments brings new interesting effects associated with disorder.