Tunnelling between non-centrosymmetric superconductors with significant spin-orbit splitting studied theoretically within a two-band treatment

TL;DR

This paper theoretically investigates tunnelling in non-centrosymmetric superconductors with strong spin-orbit coupling, revealing how the Josephson current and quasiparticle conductance are affected by the relative orientation of inversion symmetry vectors, aiding in identifying pairing states.

Contribution

It introduces a two-band theoretical model to analyze tunnelling phenomena in non-centrosymmetric superconductors, highlighting effects of spin-orbit splitting on Josephson current modulation and quasiparticle conductance features.

Findings

Josephson current can be modulated by the relative angle of inversion symmetry vectors.

Multiple steps appear in the quasiparticle current-voltage characteristics.

Proposes experimental tests including scanning tunnelling microscopy.

Abstract

Tunnelling between non-centrosymmetric superconductors with significant spin-orbit splitting is studied theoretically in a two-band treatment of the problem. We find that the critical Josephson current may be modulated by changing the relative angle between the vectors describing absence of inversion symmetry on each side of the junction. The presence of two gaps also results in multiple steps in the quasiparticle current-voltage characteristics. We argue that both these effects may help to determine the pairing states in materials like CePt$_3$Si, UIr and Cd$_2$Re$_2$O$_7$. We propose experimental tests of these ideas, including scanning tunnelling microscopy.