title: Superconductivity without nesting in LiFeAs.
abstract: We have studied the electronic structure of the nonmagnetic LiFeAs (T(c)∼18  K) superconductor using angle-resolved photoemission spectroscopy. We find a notable absence of the Fermi surface nesting, strong renormalization of the conduction bands by a factor of 3, high density of states at the Fermi level caused by a van Hove singularity, and no evidence for either a static or a fluctuating order except superconductivity with in-plane isotropic energy gaps. Our observations suggest that these electronic properties capture the majority of ingredients necessary for the superconductivity in iron pnictides.
authors.affiliation: Leibniz-Institute for Solid State Research, IFW-Dresden, D-01171 Dresden, Germany.
authors.forename: S V
authors.initials: SV
authors.lastname: Borisenko
authors.forename: V B
authors.initials: VB
authors.lastname: Zabolotnyy
authors.forename: D V
authors.initials: DV
authors.lastname: Evtushinsky
authors.forename: T K
authors.initials: TK
authors.lastname: Kim
authors.forename: I V
authors.initials: IV
authors.lastname: Morozov
authors.forename: A N
authors.initials: AN
authors.lastname: Yaresko
authors.forename: A A
authors.initials: AA
authors.lastname: Kordyuk
authors.forename: G
authors.initials: G
authors.lastname: Behr
authors.forename: A
authors.initials: A
authors.lastname: Vasiliev
authors.forename: R
authors.initials: R
authors.lastname: Follath
authors.forename: B
authors.initials: B
authors.lastname: Büchner