Orbital character and electron correlation effects on two- and three-dimensional Fermi surfaces in KFe2As2 revealed by angle-resolved photoemission spectroscopy

• Main Authors: Teppei eYoshida, Shin-ichiro eIdeta, Ichiro eNishi, Atsushi eFujimori, Ming eYi, Rob eMoore, Sung-Kwan eMo, Donghui eLu, Zhi-Xun eShen, Zahid eHussain, Kunihiro eKihou, C. H eLee, Akira eIyo, Hiroshi eEisaki, Hisatomo eHarima
• Format: Article
• Language: English
• Published: Frontiers Media S.A. 2014-04-01
• Series: Frontiers in Physics
• Subjects: electron correlation; band structure; angle-resolved photoemission spectroscopy; iron pnictide superconductor; Fermi surface
• Online Access: http://journal.frontiersin.org/Journal/10.3389/fphy.2014.00017/full

We have investigated orbital character and electron correlation effects on Fermi surfaces in the hole-overdoped iron pnictide superconductor KFe2As2, which shows a low Tc of ~4 K, by angle-resolved photoemission spectroscopy. From the polarization-dependence of the ARPES spectra, we have determined the orbital character of each Fermi surface. Electron mass renormalization of each band is quantitatively consistent with de Haas-van Alphen results. The outer beta and middle zeta Fermi surfaces show large renormalization factor of m*/mb ~6-7, while the inner Fermi surface has a smaller factor m*/mb ~2. Middle hole Fermi surface zeta has strong three-dimensionality compared to other Fermi surfaces, indicating the d3z2-r2 orbital character, which may be related to the octet-line nodes recently observed by laser ARPES. The observed orbital-dependent mass renormalization would give constraints on the pairing mechanism with line nodes of this system.