Optical conductivity and Raman scattering of iron superconductors

TL;DR

This paper presents a method to analyze optical conductivity and Raman spectra in multi-orbital iron superconductors, revealing how magnetic gaps and lattice structure influence anisotropic electronic properties.

Contribution

It introduces a novel approach using velocity and Raman vertices to interpret spectroscopic data in iron superconductors, highlighting the effects of magnetic order and lattice variations.

Findings

Optical conductivity anisotropy reflects magnetic gap differences.

Raman spectra sample both magnetic gaps.

Drude weight anisotropy is sensitive to lattice changes.

Abstract

We discuss how to analyze the optical conductivity and Raman spectra of multi-orbital systems using the velocity and the Raman vertices in a similar way Raman vertices were used to disentangle nodal and antinodal regions in cuprates. We apply this method to iron superconductors in the magnetic and non-magnetic states, studied at the mean field level. We find that the anisotropy in the optical conductivity at low frequencies reflects the difference between the magnetic gaps at the X and Y electron pockets. Both gaps are sampled by Raman spectroscopy. We also show that the Drude weight anisotropy in the magnetic state is sensitive to small changes in the lattice structure.