Geometry controlled superconducting diode and anomalous Josephson effect triggered by the topological phase transition in curved proximitized nanowires

TL;DR

This paper investigates how the topological phase transition in curved proximitized nanowires influences the Josephson effect, revealing a tunable phase that can serve as a probe for topological states and aid quantum device development.

Contribution

It introduces a detailed analysis of the anomalous Josephson phase behavior during topological transitions in curved nanowires, combining numerical and analytical methods.

Findings

The ground-state phase difference $$ varies with the spin splitting field $h$.

The phase $$ exhibits a peak around the topological transition.

The crossover region shows a superconducting diode effect.

Abstract

We study the key features of the Josephson transport through a curved semiconducting nanowire. Based on numerical simulations and analytical estimates within the framework of the Bogoliubov-de Gennes equations we find the ground-state phase difference $\varphi_0$ between the superconducting leads tuned by the spin splitting field $h$ driving the system from the topologically trivial to the nontrivial superconducting state. The phase $\varphi_0$ vanishes for rather small $h$, grows in a certain field range around the topological transition, and then saturates at large $h$ in the Kitaev regime. Both the subgap and the continuum quasiparticle levels are responsible for the above behavior of the anomalous Josephson phase. It is demonstrated that the crossover region on $\varphi_0(h)$ dependencies reveals itself in the superconducting diode effect. The resulting tunable phase battery can be used as a probe of topological transitions in Majorana networks and can become a useful element of various quantum computation devices.