Probing the Pairing Interaction and Multiple Bardasis-Schrieffer Modes Using Raman Spectroscopy

S. Maiti, T. A. Maier, T. Böhm, R. Hackl, and P. J. Hirschfeld

Phys. Rev. Lett. 117, 257001 – Published 15 December 2016

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 a 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 subleading gap structures within a microscopic pairing theory. While our conclusions are completely general, we apply our approach to interpret the specific case of $B_{1 g}$ Raman scattering in hole-doped ${BaFe}_{2} {As}_{2}$ .

Received 16 August 2016

DOI:https://doi.org/10.1103/PhysRevLett.117.257001

Physics Subject Headings (PhySH)

Multiband superconductivity Pairing mechanisms Superconducting fluctuations Superconductivity

Raman spectroscopy

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

S. Maiti¹, T. A. Maier², T. Böhm^3,4, R. Hackl³, and P. J. Hirschfeld¹

¹Department of Physics, University of Florida, Gainesville, Florida 32611
²Center for Nanophase Materials Sciences and Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6494, USA
³Walther Meissner Institut, Bayerische Akademie der Wissenschaften, 85748 Garching, Germany
⁴Fakultät für Physik E23, Technische Universität München, 85748 Garching, Germany