Revealing the superconducting state of CaC6 by angle-resolved photoelectron spectrocopy

ORAL

Abstract

We studied the electronic band structure of CaC$_{6}$ using angle-resolved photoelectron spectroscopy (ARPES). We were able to make direct connections to the DFT calculation and identify various electron- and hole-pockets both at the $\Gamma$- and K-points. Most importantly, we convincingly observed the interlayer band, which was predicted to be responsible for superconductivity and to display a near-free-electron-like dispersion. The near-circular Fermi surface of the interlayer band is clearly separate from the carbon-derived bands, which enables a pocket-dependent superconducting gap analysis near the $\Gamma$-point. Distinct electron-phonon coupling regimes were observed for the interlayer and the carbon-derived bands using self-energy analysis in agreement with previous studies.

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Authors

  • Shuolong Yang

    Stanford Institute for Materials and Energy Science;Geballe Laboratory for Advanced Materials, Department of Physics and Applied Physics, Stanford, CA

  • Jonathan Sobota

    Stanford University, Stanford Institute for Materials and Energy Science;Geballe Laboratory for Advanced Materials, Department of Physics and Applied Physics, Stanford, CA

  • Chris Howard

    London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London, UK

  • Chris Pickard

    London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London, UK

  • Makoto Hashimoto

    Stanford Institute for Materials and Energy Sciences, SLAC, CA, SLAC, SLAC National Accelerator Laboratory

  • Donghui Lu

    SSRL, SLAC National Accelerator Laboratory, Stanford Institute for Materials and Energy Sciences, SLAC, CA

  • Sung-Kwan Mo

    Advanced Light Source, Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA

  • Mark Ellerby

    London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London, UK

  • Zhi-Xun Shen

    Stanford Institute for Materials and Energy Science;Geballe Laboratory for Advanced Materials, Department of Physics and Applied Physics, Stanford, CA, Stanford University, Department of Applied Physics, Stanford University; SIMES