Miles V. Klein: Shining light on iron pnictides with Raman scattering

Our theoretical understanding of “classic” one-band superconductors such as simple metals is based on the BCS theory, which says that at low temperatures the minimum excitation energy of a single electron ( or the energy required to break a Cooper pair ) is twice Δ, the superconducting gap. As first shown by Abrikosov and collaborators this is seen in the electronic Raman scattering spectrum, an inelastic light scattering probe, as a continuum that sharply rises from zero at energy shift 2Δ, followed by a fall off at higher energy...