title: Bandwidth and Electron Correlation-Tuned Superconductivity in Rb_{0.8}Fe_{2}(Se_{1-z}S_{z})_{2}.
abstract: We present a systematic angle-resolved photoemission spectroscopy study of the substitution dependence of the electronic structure of Rb_{0.8}Fe_{2}(Se_{1-z}S_{z})_{2} (z=0, 0.5, 1), where superconductivity is continuously suppressed into a metallic phase. Going from the nonsuperconducting Rb_{0.8}Fe_{2}S_{2} to superconducting Rb_{0.8}Fe_{2}Se_{2}, we observe little change of the Fermi surface topology, but a reduction of the overall bandwidth by a factor of 2. Hence, for these heavily electron-doped iron chalcogenides, we have identified electron correlation as explicitly manifested in the quasiparticle bandwidth to be the important tuning parameter for superconductivity, and that moderate correlation is essential to achieving high T_{C}.
authors.affiliation: Department of Physics, University of California Berkeley, Berkeley, California 94720, USA.
authors.forename: M
authors.initials: M
authors.lastname: Yi
authors.affiliation: Department of Physics, University of California Berkeley, Berkeley, California 94720, USA.
authors.forename: Meng
authors.initials: M
authors.lastname: Wang
authors.affiliation: Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: A F
authors.initials: AF
authors.lastname: Kemper
authors.affiliation: Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: S-K
authors.initials: SK
authors.lastname: Mo
authors.affiliation: Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Z
authors.initials: Z
authors.lastname: Hussain
authors.affiliation: Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: E
authors.initials: E
authors.lastname: Bourret-Courchesne
authors.affiliation: Department of Physics, University of California Berkeley, Berkeley, California 94720, USA.|Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: A
authors.initials: A
authors.lastname: Lanzara
authors.affiliation: Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: M
authors.initials: M
authors.lastname: Hashimoto
authors.affiliation: Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: D H
authors.initials: DH
authors.lastname: Lu
authors.affiliation: Stanford Institute of Materials and Energy Sciences, Stanford University, Stanford, California 94305, USA.|Departments of Physics and Applied Physics, and Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA.
authors.forename: Z-X
authors.initials: ZX
authors.lastname: Shen
authors.affiliation: Department of Physics, University of California Berkeley, Berkeley, California 94720, USA.|Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.|Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA.
authors.forename: R J
authors.initials: RJ
authors.lastname: Birgeneau