Orbital tunable 0-$\pi$ transitions in Josephson junctions with noncentrosymmetric topological superconductors

TL;DR

This paper explores how multi-orbital noncentrosymmetric superconductors induce tunable 0-$f extpi$ Josephson junction transitions, revealing new control mechanisms for superconducting phase states.

Contribution

It demonstrates that multi-band $d^{ extpm}$-wave states in noncentrosymmetric superconductors enable highly controllable 0-$f extpi$ transitions in Josephson junctions, a novel finding.

Findings

Phase state can be toggled via electron filling, spin-orbit coupling, and junction transparency.

Multi-band $d^{ extpm}$-wave pairing drives unexpected Josephson effects.

Orbital and electrical control of Josephson response is intrinsic to the system.

Abstract

We investigate the Josephson transport properties in a Josephson junction consisting of a conventional $s$-wave superconductor coupled to a multi-orbital noncentrosymmetric superconductor marked by an orbitally driven inversion asymmetry and isotropic interorbital spin-triplet pairing. Contrary to the canonical single band noncentrosymmetric superconductor, we demonstrate that the local interorbital spin-triplet pairing is tied to the occurrence of sign-changing spin-singlet pair amplitude on different bands with $d$-wave symmetry. Such multi-band $d^{\pm}$-wave state is a unique superconducting configuration that drives unexpected Josephson effects with 0-$\pi$ transitions displaying a high degree of electronic control. Remarkably, we find that the phase state of a noncentrosymmetric/$s$-wave Josephson junction can be toggled between 0 and $\pi$ in multiple ways through a variation of electron filling, strength of the spin-orbital coupling, amplitude of the inversion asymmetry interaction, and junction transparency. These results highlight an intrinsic orbital and electrical tunability of the Josephson response and provide unique paths to unveil the nature of unconventional multiorbital superconductivity as well as inspire innovative designs of Josephson quantum devices.