Topological $s$-wave superconductors driven by electron correlation

TL;DR

This paper demonstrates that electron interactions can induce topological phases in s-wave superconductors, revealing topological states in doped Mott insulators through exact solutions and boundary mode analysis.

Contribution

It provides an exact solution showing how electron correlations can turn trivial s-wave superconductors into topological ones without spin-orbit coupling.

Findings

Fermion parity varies with electron interaction

Topological phase diagram mapped out

Boundary zero modes confirmed

Abstract

It is interesting to ask whether electron interaction can turn a topologically trivial superconductor into a nontrivial one without the presence of spin-obital coupling. In this paper we solve a correlated $s$-wave superconducting model exactly. The variation of the fermion number parity of the superconducting ground state as a function of the electron interaction is calculated and the topological phase diagram is obtained. Topological $s$-wave superconducting states are revealed in the doped Mott insulators, which is further confirmed by the numerical investigation of the topological boundary zero mode.