Bandwidth and Electron Correlation-Tuned Superconductivity in Rb_{0.8}Fe_{2}(Se_{1-z}S_{z})_{2}

M Yi; Meng Wang; A F Kemper; S-K Mo; Z Hussain; E Bourret-Courchesne; A Lanzara; M Hashimoto; D H Lu; Z-X Shen; R J Birgeneau

doi:10.1103/PhysRevLett.115.256403

Bandwidth and Electron Correlation-Tuned Superconductivity in Rb_{0.8}Fe_{2}(Se_{1-z}S_{z})_{2}

Phys Rev Lett. 2015 Dec 18;115(25):256403. doi: 10.1103/PhysRevLett.115.256403. Epub 2015 Dec 15.

Authors

M Yi¹, Meng Wang¹, A F Kemper², S-K Mo³, Z Hussain³, E Bourret-Courchesne⁴, A Lanzara^{1

4}, M Hashimoto⁵, D H Lu⁵, Z-X Shen^{6

7}, R J Birgeneau^{1

4

8}

Affiliations

¹ Department of Physics, University of California Berkeley, Berkeley, California 94720, USA.
² Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
³ Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
⁴ Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
⁵ Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
⁶ Stanford Institute of Materials and Energy Sciences, Stanford University, Stanford, California 94305, USA.
⁷ Departments of Physics and Applied Physics, and Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA.
⁸ Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA.

PMID: 26722933
DOI: 10.1103/PhysRevLett.115.256403

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}.