Spin-sensitive Long-ranged Proximity Effect for Triplet Superconductors

TL;DR

This paper proposes a simple, spin-sensitive proximity effect method in ferromagnet–triplet superconductor bilayers to identify spin-triplet pairing, distinguish states by magnetic field orientation, and observe long-range effects without magnetic inhomogeneities.

Contribution

It introduces a novel, experimentally feasible approach to detect and characterize spin-triplet superconductivity using a bilayer structure and magnetic field orientation.

Findings

Proximity effect is long-ranged despite exchange fields.

Orientation of magnetic field distinguishes triplet states.

Method can be verified by STM spectroscopy.

Abstract

The discovery of noncentrosymmetric superconductors, such as CePt$_3$Si, and chiral superconductors, such as Sr$_2$RuO$_4$, calls for experimental methods to identify the presence of spin-triplet pairing. We here demonstrate a method which accomplishes this in an appealingly simple manner: a spin-sensitive proximity effect in a ferromagnet$\mid$triplet superconductor bilayer. It is shown how the orientation of the field can be used to unambiguously distinguish between different spin-triplet states. Moreover, the proximity effect becomes long-ranged in spite of the presence of an exchange field and even without any magnetic inhomogeneities, in contrast to conventional S$\mid$F junctions. Our results can be verified by STM-spectroscopy and could be useful as a tool to characterize the pairing state in unconventional superconducting materials.