Josephson Effect in Noncentrosymmetric Superconductor Junctions

TL;DR

This paper investigates how the Josephson current between noncentrosymmetric superconductors varies with different pairing symmetries and highlights the role of topologically protected surface states in these phenomena.

Contribution

It demonstrates the dependence of Josephson current behavior on the relative amplitudes of singlet and triplet pairing components in noncentrosymmetric superconductors.

Findings

Distinct Josephson current behaviors for different pairing dominance.

Zero-energy surface bound states influence current characteristics.

Josephson current reflects the topological and pairing properties of the superconductors.

Abstract

We discuss the Josephson current between two noncentrosymmetric superconductors. The coexistence of superconducting order parameters between spin-singlet $\Delta_{\text{S}}$ and helical p-wave spin-triplet $\Delta_{\text{T}}$ enriches a variety of low-temperature behavior of Josephson current depending on their relative amplitudes. We will show that characteristic behaviors of the Josephson current for $\Delta_{\text{S}} > \Delta_{\text{T}}$ are clearly different from those for $\Delta_{\text{S}} < \Delta_{\text{T}}$. The topologically protected zero-energy surface bound states are responsible for the clear difference. We conclude that the Josephson current well reflects character of the topological surface states and the pairing symmetry of noncentrosymmetric superconductors.