Optical conductivity of superconducting Sr_2RuO_4

TL;DR

This paper calculates the optical conductivity of Sr_2RuO_4 superconductors, highlighting the impact of interband impurity scattering and proposing experimental tests to distinguish between competing triplet superconductivity models.

Contribution

It provides a detailed theoretical analysis of optical conductivity in multiband superconductors, emphasizing the role of impurity scattering in Sr_2RuO_4.

Findings

Interband impurity scattering significantly affects optical spectra.

New structures in tunneling density of states and optical spectrum identified.

Results offer a way to differentiate superconductivity models in Sr_2RuO_4.

Abstract

We compute the optical conductivity of 2D f-wave superconductors and also of the multigap model proposed recently by Zhitomirsky and Rice at T=0K in the Born limit. The presence of interband impurity scattering was found to play an important role: the contributions from the two bands mix up, and new structures are seen in the tunneling density of states and in the optical spectrum as well, corresponding to interband transitions. This will provide a sensitive test in selecting the competing models for the triplet superconductivity in Sr_2RuO_4.