A comprehensive study of chemical substitution effects on superconductivity in LaPt4Ge12

ORAL

Abstract

The compound PrPt$_4$Ge$_{12}$ has attracted significant attention following observations of signatures of unconventional superconductivity such as time reversal symmetry breaking from $\mu$SR measurements. In contrast, LaPt$_4$Ge$_{12}$ is a conventional BCS-type superconductor, interestingly, with the same superconducting transition temperature, $T_c$, as PrPt$_4$Ge$_{12}$ ($T_c$ = 8 K). To elucidate the properties of superconductivity in PrPt$_4$Ge$_{12}$, the system La$_{1-x}$Ce$_x$Pt$_4$Ge$_{12}$ was investigated and the results are compared to our previous work on Pr$_{1-x}$Ce$_x$Pt$_4$Ge$_{12}$. Measurements of magnetic susceptibility, electrical resistivity, and specific heat were performed demonstrating that $T_c$ is suppressed more rapidly in La$_{1-x}$Ce$_x$Pt$_4$Ge$_{12}$ than in Pr$_{1-x}$Ce$_x$Pt$_4$Ge$_{12}$. Specific heat measurements reveal a crossover in the temperature dependence of the superconducting state of La$_{1-x}$Ce$_x$Pt$_4$Ge$_{12}$, changing from a power law for $x$ = 0 to an exponential for the Ce-substituted samples, possible evidence of a transition from a multiband to a single-band superconducting energy gap. Th substitution for La did not produce the crossover.

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Authors

  • Kevin Huang

    Physics Department, UC San Diego

  • D. Yazici

    Physics Department, UC San Diego, Department of Physics, University of California, San Diego, UC, San Diego, Department of Physics, University of California, San Diego, La Jolla, CA 92093, USA

  • B. White

    University of California, San Diego, Physics Department, UC San Diego, Department of Physics, University of California, San Diego, Department of Physics, University of California, San Diego, La Jolla, CA 92093, USA

  • Alexander Breindel

    Physics Department, UC San Diego

  • Naveen Pouse

    Physics Department, UC San Diego, Department of Physics, University of California, San Diego

  • Lei Shu

    Physics Department, Fudan University, Fudan University

  • Brian Maple

    University of California, San Diego, Physics Department, UC San Diego, Department of Physics, University of California, San Diego, Physics/UC San Diego, Department of Physics, University of California, San Diego, La Jolla, CA 92093, USA, Department. of Physics, U. of California, San Diego