Scanning tunneling microscopy and spectroscopy measurements of heavy fermion compound CeCoIn$_{5}$

ORAL

Abstract

The heavy fermion compound CeCoIn$_{5}$ has a rich electronic phase diagram as a function of doping, pressure, and magnetic field. The interaction between Ce's f-electrons and the conduction bands is expected to form Kondo screening of the spins starting at relatively high temperatures. Below 2.3 K CeCoIn$_{5}$ is known to exhibit an unconventional superconducting ground state. We present scanning tunneling microscopy and spectroscopy (STM/S) as a function of temperature on CeCoIn$_{5}$. The in-situ cleaved samples show three different layer terminations. Acquiring structural information from STM topographies we identify the chemical character of each layer. STS measurements, on all surfaces, performed over a wide range of temperature show the rapid development of an energy gap in the tunneling density of states near the onset of coherence ($\sim $ 40 K). The origin of the observed energy gap and its relation to heavy band hybridization is addressed.

*Work primarily supported by DOE-BES. Infrastructure at Princeton Nanoscale Microscopy Laboratory also supported by NSF-DMR, NSF-MRSEC programme through PCCM, and the W. M. Keck foundation.

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Authors

  • Eduardo da Silva Neto

    • Princeton University

  • Pegor Aynajian

    • Princeton University

  • Colin Parker

    • Brookhaven National Laboratory
    • Princeton University

  • Paul Tobash

    • Los Alamos National Laboratory

  • Eric Bauer

    • Los Alamos Natl. Lab., NM, USA
    • Los Alamos National Lab, MPA-CMMS
    • Los Alamos Nat. Lab.
    • MPA-CMMS, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
    • Los Alamos National Laboratory
    • Los Alamos National Laboratory, Los Alamos, NM 87545

  • Ali Yazdani

    • Department of Physics, Princeton University
    • Physics Department, Princeton University
    • Princeton University