Pinpointing gap minima in Ba(Fe0.94Co0.06)2As2 via band-structure calculations and electronic Raman scattering

A detailed knowledge of the gap structure for the Fe-pnictide superconductors is still rather rudimentary with several conflicting reports of either nodes, deep gap minima, or fully isotropic gaps on the Fermi-surface sheets, both in the k(x)-k(y) plane and along the c axis. In this Rapid Communication, we present considerations for electronic Raman scattering which can help clarify the gap structure and topology using different light-scattering geometries. Using density-functional calculations for the Raman vertices, it is shown that the location of the gap minima may occur on loops stretching over a portion of the c axis in Ba(Fe0.94Co0.06)(2)As-2.