Superconductivity and possible charge Kondo effect in Tl-doped PbTe

ORAL

Abstract

We report results of low-temperature thermodynamic and transport measurements of Pb$_{1-x}$Tl$_x$Te single crystals for Tl concentrations up to the solubility limit of approximately 1.5$\%$. For $x$ greater than approximately 0.3$\%$, the samples superconduct with a maximum $T_c$ of approximately 1.4 K for the highest Tl concentrations. For all doped samples, we observe an anomalous low-temperature upturn in the resistivity that saturates below 1 K and that scales in magnitude with the Tl concentration. The temperature and field dependence of this upturn are consistent with Kondo-like behavior of a nonmagnetic degenerate two-level system.

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Authors

  • Y. Matsushita

    • Department of Materials Science and Engineering, Stanford University

  • H. Bluhm

    • Department of Physics, Stanford University

  • Theodore Geballe

  • I. R. Fisher

    • Dept. of Applied Physics, Stanford University
    • Department of Applied Physics, Stanford University