Probing the pairing interaction and multiple Bardasis-Schrieffer modes using Raman spectroscopy

Abstract

In unconventional superconductors, understanding the form of the pairing interaction is the primary goal. In this regard, Raman spectroscopy is a very useful tool, as it identifies the ground state and also the subleading pairing channels by probing collective modes. Here we propose a general theory for multiband Raman response and identify new features in the spectrum that can provide a robust test for a pairing theory. We identify multiple Bardasis-Schrieffer type collective modes and connect the weights of these modes to the sub-leading gap structures within a microscopic pairing theory. The conclusions are completely general, and we apply our approach to interpret the B1g Raman scattering in hole-doped BaFe2As2.

5pp+7pp, 4 figures

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Cited by in corpus (1)

• Superconductivity and electronic fluctuations in Ba${}_{1-x}$K${}_x$Fe${}_2$As${}_2$ studied by Raman scattering