title: Orbital characters and electronic correlations in KCo2Se2.
abstract: We report a comprehensive study of the tridimensional nature and orbital characters of the low-energy electronic structure in KCo2Se2, using polarization- and photon energy-dependent angle-resolved photoemission spectroscopy. We observed one electron-like Fermi surface (FS) at the Brillouin zone (BZ) center, four electron-like FSs centered at the BZ corner, and one hole-like FS at the BZ boundary. The FSs show weak dispersion along the kz direction, indicating the near-two-dimensional nature of FSs in KCo2Se2. In combination with the local-density approximation calculations, we determined the orbital characters of the low-energy electronic bands, which are mainly derived from the Co 3d orbital, mixed with part of the Se 4p states. The [Formula: see text] orbital gives a significant contribution to the band crossing the Fermi level. A band renormalization of about 1.6 is needed to capture the essential dispersive features, which suggests that electronic correlations are much weaker than that in KyFe2-xSe2.
authors.affiliation: Department of Physics, Renmin University, Beijing 100872, People's Republic of China. Institute for Solid State Research, IFW Dresden, Dresden 01171, Germany. State Key Laboratory of Functional Materials for Informatic, SIMIT, Chinese Academy of Sciences, Shanghai 200050, People's Republic of China.
authors.forename: Z H
authors.initials: ZH
authors.lastname: Liu
authors.forename: Y G
authors.initials: YG
authors.lastname: Zhao
authors.forename: Y
authors.initials: Y
authors.lastname: Li
authors.forename: L L
authors.initials: LL
authors.lastname: Jia
authors.forename: Y P
authors.initials: YP
authors.lastname: Cai
authors.forename: S
authors.initials: S
authors.lastname: Zhou
authors.forename: T L
authors.initials: TL
authors.lastname: Xia
authors.forename: B
authors.initials: B
authors.lastname: Büchner
authors.forename: S V
authors.initials: SV
authors.lastname: Borisenko
authors.forename: S C
authors.initials: SC
authors.lastname: Wang