title: Anisotropic energy gaps of iron-based superconductivity from intraband quasiparticle interference in LiFeAs.
abstract: If strong electron-electron interactions between neighboring Fe atoms mediate the Cooper pairing in iron-pnictide superconductors, then specific and distinct anisotropic superconducting energy gaps Δ(i)(k) should appear on the different electronic bands i. Here, we introduce intraband Bogoliubov quasiparticle scattering interference (QPI) techniques for determination of Δ(i)(k) in such materials, focusing on lithium iron arsenide (LiFeAs). We identify the three hole-like bands assigned previously as γ, α(2), and α(1), and we determine the anisotropy, magnitude, and relative orientations of their Δ(i)(k). These measurements will advance quantitative theoretical analysis of the mechanism of Cooper pairing in iron-based superconductivity.
authors.affiliation: Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973, USA.
authors.forename: M P
authors.initials: MP
authors.lastname: Allan
authors.forename: A W
authors.initials: AW
authors.lastname: Rost
authors.forename: A P
authors.initials: AP
authors.lastname: Mackenzie
authors.forename: Yang
authors.initials: Y
authors.lastname: Xie
authors.forename: J C
authors.initials: JC
authors.lastname: Davis
authors.forename: K
authors.initials: K
authors.lastname: Kihou
authors.forename: C H
authors.initials: CH
authors.lastname: Lee
authors.forename: A
authors.initials: A
authors.lastname: Iyo
authors.forename: H
authors.initials: H
authors.lastname: Eisaki
authors.forename: T-M
authors.initials: TM
authors.lastname: Chuang