Band and momentum dependent electron dynamics in superconducting ${\rm Ba(Fe_{1-x}Co_{x})_2As_2}$ as seen via electronic Raman scattering

TL;DR

This study uses electronic Raman scattering to reveal complex, band-dependent electron dynamics and possible nodal gaps in superconducting Ba(Fe_{1-x}Co_{x})_2As_2, indicating multiple competing superconducting states.

Contribution

It provides detailed insights into band and momentum anisotropy of electron dynamics and gap structure in Ba(Fe_{1-x}Co_{x})_2As_2 using Raman scattering, highlighting complex interactions.

Findings

Strong band and momentum anisotropy of electron dynamics

Presence of low energy spectral weight suggesting nodal gaps

Indications of multiple competing superconducting states

Abstract

We present details of carrier properties in high quality ${\rm Ba(Fe_{1-x}Co_{x})_2As_2}$ single crystals obtained from electronic Raman scattering. The experiments indicate a strong band and momentum anisotropy of the electron dynamics above and below the superconducting transition highlighting the importance of complex band-dependent interactions. The presence of low energy spectral weight deep in the superconducting state suggests a gap with accidental nodes which may be lifted by doping and/or impurity scattering. When combined with other measurements, our observation of band and momentum dependent carrier dynamics indicate that the iron arsenides may have several competing superconducting ground states.