Re-entrant topological order in strongly correlated nanowire due to Rashba spin-orbit coupling

TL;DR

This paper explores how Rashba spin-orbit coupling influences topological phases in strongly correlated 1D superconductors, revealing re-entrant topological behavior due to band folding and sub-band formation, with potential experimental realizations.

Contribution

It demonstrates the re-entrant topological order caused by RSOC-induced band folding in correlated nanowires and proposes experimental setups to observe this effect.

Findings

RSOC causes band folding and energy gap formation at the Brillouin zone boundary.

Topological phases can be toggled by tuning the chemical potential within sub-band gaps.

In-plane magnetic fields can control RSOC effects in nanowires with strong electron correlations.

Abstract

The effect of the Rashba spin orbit coupling (RSOC) on the topological properties of the one-dimensional (1D) extended $s$-wave superconducting Hamiltonian, in the presence of strong electron-electron correlation, is investigated. It is found that a non-zero RSOC increases the periodicity of the effective Hamiltonian, which results in the folding of the Brillouin zone (BZ), and consequently in the emergence of an energy gap at the boundary of the BZ. Essentially the initial single band is divided into number of sub-bands. If the chemical potential lies inside the energy gaps (sub-bands) then the phase is topologically trivial (non trivial). This is the origin of re-entrant nature of the existent topological properties. The emergence of sub-bands allows us to drive the system in and out of the topological phase by the proper tuning of the chemical potential. A heterostructure involving van der Waals materials and a 1D Moire pattern for an investigation of the predicted effect has also been proposed. We also discuss how in-plane magnetic field can be used to control the RSOC coupling and induced periodicity in depleted InAs nanowire in which evidence of strong electron-electron correlation has been found.