Proposed Detection of the Topological Phase in Ring-Shaped Semiconductor-Superconductor Nanowires Using Coulomb Blockade Transport

TL;DR

This paper proposes a method to detect topological phase transitions in ring-shaped semiconductor-superconductor nanowires by observing changes in flux periodicity in Coulomb blockade transport, linking it to Josephson current behavior.

Contribution

It introduces a novel approach to identify topological phases via flux periodicity changes in Coulomb blockade measurements in ring structures.

Findings

Flux periodicity shifts from h/2e to h/e at the topological transition.

h/e periodicity correlates with 4π Josephson effect.

Method provides a new experimental signature for topological phases.

Abstract

In semiconductor-superconductor hybrid structures a topological phase transition is expected as a function of chemical potential or magnetic field strength. We show that signatures of this transition can be observed in nonlinear Coulomb blockade transport through a ring shaped structure. In particular, for a fixed electron parity of the ring, the flux periodicity of the neutral excitation spectrum changes from the usual h/2e periodicity to a characteristic h/e periodicity when tuning the system from the topologically trivial to the nontrivial phase. We relate the h/e periodicity to the recently predicted 4\pi periodicity of the Josephson current across a junction formed by two topological superconductors.