Dimerization-induced topological superconductivity in a Rashba nanowire

TL;DR

This paper investigates how dimerization in a Rashba nanowire can induce topological superconductivity and Majorana modes, revealing a new mechanism distinct from uniform nanowires and analyzing its stability and experimental detection.

Contribution

It demonstrates that dimerization can induce topological phases in Rashba nanowires, providing analytical insights and discussing experimental detection methods.

Findings

Dimerization causes band inversion leading to topological phases.

Topological phases are stable against electrostatic disorder.

Dimerization-induced topological phases can suppress uniform nanowire phases.

Abstract

We analyze influence of a dimerization on the topological phases of the Rashba nanowire proximitized to a superconducting substrate. We find that periodic alternations of the hopping integral and spin-orbit coupling can lead to band inversion, inducing transition to topologically nontrivial superconducting phase that hosts the Majorana zero-energy modes. This "dimerization-induced topological superconductivity" completely repels the topological phase of the uniform nanowire, whenever they happen to overlap. We provide an analytical justification for this puzzling behavior based on the symmetry/parity considerations and discuss feasible spectroscopic methods for its empirical observation. We also test stability of the topological superconducting phases against electrostatic disorder.