Electronic Raman scattering in non-centrosymmetric superconductors

TL;DR

This paper develops a theoretical framework for understanding how polarization affects electronic Raman scattering in non-centrosymmetric superconductors, predicting distinctive spectral features related to their mixed singlet-triplet pairing states.

Contribution

It provides analytical expressions for Raman vertices and polarization-dependent spectra, highlighting unique signatures of the superconducting order parameter in these materials.

Findings

Prediction of a two-peak structure in spectra

Different power laws depending on singlet-triplet ratio

Identification of spectral fingerprints of the condensate

Abstract

We formulate a theory for the polarization-dependence of the electronic (pair-breaking) Raman response for the recently discovered non-centrosymmetric superconductors in the clean limit at zero temperature. Possible applications include the systems CePt$_3$Si and Li$_2$Pd$_x$Pt$_{3-x}$B which reflect the two important classes of the involved spin-orbit coupling. We provide analytical expressions for the Raman vertices for these two classes and calculate the polarization dependence of the electronic spectra. We predict a two-peak structure and different power laws with respect to the unknown relative magnitude of the singlet and triplet contributions to the superconducting order parameter, revealing a large variety of characteristic fingerprints of the underlying condensate.