Orbital selective pairing in Fe-based superconductors

Monday, October 23, 2017 - 2:30pm

I discuss the influence on spin-fluctuation pairing theory of orbital selective strong
correlation effects in Fe-based superconductors, particularly Fe chalcogenide systems. This approach provides a
way to incorporate the  reduced coherence of quasiparticle occupying specific orbital
states via suppression of pair scattering processes involving those less coherent states
I show that this paradigm yields remarkably good agreement with the experimentally
observed anisotropic gap structures in both bulk and monolayer FeSe, as well as LiFeAs,
indicating that orbital selective Cooper pairing plays a key role in the more strongly
correlated iron-based superconductors.  I focus particularly on recent STM quasiparticle
experiments which determine the gap magnitude structure in Fe chalcogenide systems, and show
how the data can be used to extract the phase structure as well.

3 Le Conte Hall
University of Florida