Exciting odd frequency equal-spin-triplet correlations at metal-superconductor interfaces

TL;DR

This paper predicts the emergence of odd frequency equal-spin-triplet correlations at metal-superconductor interfaces, highlighting their relation to dissipation-less spin currents and the role of spin-flip scattering.

Contribution

It demonstrates that spin-flip scattering at the interface induces equal-spin-triplet correlations without mixed spin-triplet correlations, a novel insight into superconductor junction behavior.

Findings

Equal-spin-triplet correlations are excited by spin-flip scattering.

These correlations are absent without spin-flip scattering.

Results align with measurements of local magnetization and spin-polarized states.

Abstract

We predict the occurrence of odd frequency equal-spin-triplet correlations at a normal metal-superconductor junction. This result is significant because equal-spin-triplet correlations are associated with the presence of dissipation-less pure spin current. Inserting a spin-flipper at the interface of a normal metal-superconductor junction excites equal-spin-triplet correlations. The existence of odd frequency equal-spin-triplet correlations in absence of odd frequency mixed spin-triplet correlations is the main take-home message of this work. It tallies well with the measured local magnetization density of states and spin-polarized local density of states at the interface. The importance of spin-flip scattering to the obtained results is manifest when we compare our normal metal-spin flipper-superconductor junction to other hybrid junctions where either only spin mixing or both spin mixing and spin-flip scattering are present.