Interaction Driven Floquet Engineering of Topological Superconductivity in Rashba Nanowires

TL;DR

This paper investigates how periodic driving and strong electron-electron interactions in Rashba nanowires can induce topological superconductivity, revealing that interactions promote topological phases even with small Zeeman gaps.

Contribution

It provides an analytical and numerical analysis showing that interactions enhance Floquet Zeeman gaps and facilitate topological phases in driven Rashba nanowires, expanding understanding of Floquet engineering.

Findings

Interactions suppress superconducting gap

Interactions enhance Floquet Zeeman gap

Topological phase achieved with small initial Zeeman gap

Abstract

We analyze, analytically and numerically, a periodically driven Rashba nanowire proximity coupled to an $s$-wave superconductor using bosonization and renormalization group analysis in the regime of strong electron-electron interactions. Due to the repulsive interactions, the superconducting gap is suppressed, whereas the Floquet Zeeman gap is enhanced, resulting in a higher effective value of $g$-factor compared to the non-interacting case. The flow equations for different coupling constants, velocities, and Luttinger-liquid parameters explicitly establish that even for small initial values of the Floquet Zeeman gap compared to the superconducting proximity gap, the interactions drive the system into the topological phase and the interband interaction term helps to achieve larger regions of the topological phase in parameter space.