ARPES studies of Na0.7CoO2 system

ORAL

Abstract

We have carried out a detailed (and first) angle-resolved photoemission study of Na0.7CoO2, the host material of the superconducting cobaltate series. Our results show a hole-type Fermi surface, a strongly renormalized quasiparticle band, a small Fermi velocity, and a large Hubbard U. The quasiparticle band crosses the Fermi level from M toward suggesting a negative sign of effective single-particle hopping teff (about 10 meV) which is on the order of magnetic exchange coupling J in this system. Temperature dependence of quasiparticles shows that spectral weight is well defined in the T-linear resistivity (non-Fermi-liquid) regime. Unusually small single-particle hopping and unconventional quasiparticle dynamics may have implications for understanding the phase of matter realized in this new class of strongly interacting quantum system.

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Authors

  • Dong Qian

    • Department of Physics, Princeton University

  • M.Z. Hasan

    • Joseph Henry Laboratories, Department of Physics, Princeton University

  • Y.-D. Chuang

  • A. Kuprin

  • A.V. Fedorov

  • R. Kimmerling

  • E. Rotenberg

  • Z. Hussain

  • H. Koh

    • Advanced Light Source, Lawrence Berkeley National Laboratory

  • N.S. Rogado

  • M.L. Foo

  • R.J. Cava

    • Department of Chemistry, Princeton University, Princeton