Landau Renormalizations of Superfluid density in Heavy Fermion Superconductor CeCoIn5

Abstract

The formation of heavy fermion bands can occur by means of the conversion of a periodic array of local moments into itinerant electrons via the Kondo effect and the huge consequent Fermi-liquid renormalizations. Leggett predicted for liquid ${}^3$He that Fermi-liquid renormalizations change in the superconducting state, leading to a temperature dependence of the London penetration depth~$\Lambda$ quite different from that in the BCS theory. Using Leggett's theory, as modified for heavy fermions, it is possible to extract from the measured temperature dependence of $\Lambda$ in high quality samples both Landau parameters $F_0^s$ and $F_1^s$; this has never been accomplished before. A modification of the temperature dependence of the specific heat $C_{\mathrm{el}}$, related to that of $\Lambda$, is also expected. We have carefully determined the magnitude and temperature dependence of $\Lambda$ in CeCoIn${}_5$ by muon spin relaxation rate measurements to obtain $F_0^s=36\pm 1$ and $F_1^s=1.2\pm 0.3$, and find a consistent change in the temperature dependence of electronic specific heat $C_{\mathrm{el}}$. This, the first determination of $F_1^s$ with a value~$\ll F_0^s$ in a heavy fermion compound, tests the basic assumption of the theory of heavy fermions, that the frequency dependence of the self-energy is much more important than its momentum dependence.

Accepted by Phys. Rev. Lett

References in corpus (4)

• Spin resonance in the d-wave superconductor CeCoIn5
• Unpaired Electrons in the Heavy-Fermion Superconductor CeCoIn_{5}
• Muon spin rotation studies of electronic excitations and magnetism in the vortex cores of superconductors
• Strong pressure dependence of the magnetic penetration depth in single crystals of the heavy fermion superconductor CeCoIn5 studied by muon spin rotation

Cited by in corpus (2)

• Theory of Scanning Tunneling Spectroscopy: from Kondo Impurities to Heavy Fermion Materials
• Superconducting gap structure in ambient-pressure-grown $\mathrm{La}{\mathrm{O}}_{0.5}{\mathrm{F}}_{0.5}\mathrm{Bi}{\mathrm{S}}_2$