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arXiv · 1510.04520

Universal Heat Conduction in Ce1-xYbxCoIn5: Evidence for Robust Nodal d-wave Superconducting Gap

Y. Xu·J. K. Dong·L. I. Lum·J. Zhang·X. C. Hong·L. P. He·K. F. Wang·Y. C. Ma·C. Petrovic·M. B. Maple·L. Shu·S. Y. Li
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Abstract

In heavy-fermion superconductor Ce$_{1-x}$Yb$_x$CoIn$_5$ system, Yb doping was reported to cause a possible change from nodal $d$-wave superconductivity to a fully gapped $d$-wave molecular superfluid of composite pairs near $x \approx$ 0.07 (nominal value $x_{nom}$ = 0.2). Here we present systematic thermal conductivity measurements on Ce$_{1-x}$Yb$_x$CoIn$_5$ ($x$ = 0.013, 0.084, and 0.163) single crystals. The observed finite residual linear term $\kappa_0/T$ is insensitive to Yb doping, verifying the universal heat conduction of nodal $d$-wave superconducting gap in Ce$_{1-x}$Yb$_x$CoIn$_5$. Similar universal heat conduction is also observed in CeCo(In$_{1-y}$Cd$_y$)$_5$ system. These results reveal robust nodal $d$-wave gap in CeCoIn$_5$ upon Yb or Cd doping.

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Y. Xu, J. K. Dong, L. I. Lum, J. Zhang, X. C. Hong, L. P. He, K. F. Wang, Y. C. Ma, C. Petrovic, M. B. Maple, L. Shu, S. Y. Li. 2015-10-15. Universal Heat Conduction in Ce1-xYbxCoIn5: Evidence for Robust Nodal d-wave Superconducting Gap. https://doi.org/10.1103/physrevb.93.064502

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