Thermal Conductivity of the Pyrochlore Superconductor KOs2O6: Strong Electron Correlations and Fully Gapped Superconductivity

Abstract

To elucidate the nature of the superconducting ground state of the geometrically frustrated pyrochlore KOs2O6 (Tc=9.6K), the thermal conductivity was measured down to low temperatures (~Tc/100). We found that the quasiparticle mean free path is strikingly enhanced below a transition at Tp=7.5K, indicating enormous electron inelastic scattering in the normal state. In a magnetic field the conduction at T ->0K is nearly constant up to ~0.4Hc2, in contrast with the rapid growth expected for superconductors with an anisotropic gap. This unambiguously indicates a fully gapped superconductivity, in contrast to the previous studies. These results highlight that KOs2O6 is unique among superconductors with strong electron correlations.

5 pages, 4 figures, accepted for publication in Phys. Rev. Lett

References in corpus (24)

• Heavy fermion superconductivity and magnetic order in non-centrosymmetric $CeP{t}_{3}Si$
• Angular Position of Nodes in the Superconducting Gap of Quasi-2D Heavy-Fermion Superconductor CeCoIn_5
• Universal Heat Conduction in YBa_2Cu_3O_6.9
• Universality in heavy-fermion systems with general degeneracy
• The ground state of heavily-overdoped non-superconducting La${}_{2-x}$Sr${}_x$CuO${}_4$
• Line nodes in the superconducting gap function of noncentrosymmetric CePt_3Si
• Thermal conductivity of single crystalline MgB_2
• New Pyrochlore Oxide Superconductor RbOs2O6
• Transport Properties of d-Wave Superconductors in the Vortex State
• Superconductivity in the Correlated Pyrochlore Cd_2Re_2O_7
• New beta-Pyrochlore Oxide Superconductor CsOs2O6
• Correlation Effects and Structural Dynamics in the $\beta$-Pyrochlore Superconductor KOs${}_2$O${}_6$
• Highly Anisotropic Gap Function in Borocarbide Superconductor LuNi_2B_2C
• Deviation from the Kadowaki-Woods relation in Yb-based intermediate-valent systems
• Mass enhancement, correlations, and strong coupling superconductivity in the beta-pyrochlore KOs2O6
• Anomalous quasiparticle transport in the superconducting state of CeCoIn5
• Superconductivity in Geometrically Frustrated Pyrochlore RbOs2O6
• Second Anomaly in the Specific Heat of beta-Pyrochlore Oxide Superconductor KOs2O6
• Pressure effects on the transition temperature and the magnetic field penetration depth in the pyrochlore superconductor RbOs_2O_6
• Possible Anisotropic Order Parameter in Pyrochlore Superconductor KOs${}_2$O${}_6$ Probed by Muon Spin Rotation
• Synthesis of superconducting pyrochlore RbOs2O6
• Evidence for s-wave superconductivity in the new beta-pyrochlore oxide RbOs2O6
• Metal-to-Insulator Transition, Spin Gap Generation, and Charge Ordering in Geometrically Frustrated Electron Systems
• Intrinsic thermodynamic properties of the pyrochlore superconductor RbOs2O6 extracted by condensation energy analysis

Cited by in corpus (26)

• Exotic Superconducting Properties in the Electron-Hole Compensated Heavy Fermion `Semimetal' URu2Si2
• Evidence for superconducting gap nodes in the zone-centered hole bands of KFe2As2 from magnetic penetration-depth measurements
• Nodal Structure of Unconventional Superconductors Probed by the Angle Resolved Thermal Transport Measurements
• Extremely strong-coupling superconductivity and anomalous lattice properties in the beta-pyrochlore oxide KOs2O6
• Rattling-Induced Superconductiviy in the Beta-Pyrochlore Oxides AOs2O6
• Momentum Dependence of the Nematic Order Parameter in Iron-Based Superconductors
• NMR Observation of Rattling Phonons in the Pyrochlore Superconductor KOs2O6
• Low-Temperature and High-Energy-Resolution Laser Photoemission Spectroscopy
• Effects of Rattling Phonons on the Quasiparticle Excitation and Dynamics in the Superconducting $\beta$-Pyrochlore KOs${}_2$O${}_6$
• Uncommonly High Upper Critical Field in the Superconducting KOs${}_2$O${}_6$ Pyrochlore
• Strong coupling superconductivity mediated by three-dimensional anharmonic phonons
• Neutron Scattering Study of the Localized Mode in the beta-Pyrochlore Superconductors AOs2O6
• Flux Line Lattice Melting and the Formation of a Coherent Quasiparticle Bloch State in the Ultraclean URu${}_2$Si${}_2$ Superconductor
• Superconducting Transition in the $\beta$-Pyrochlore AOs${}_2$O${}_6$ (A=Cs, Rb, K) under Pressure
• A Possible Phase Transition in beta-pyrochlore Compounds
• A second phase transition and superconductivity in the beta-pyrochlore oxide KOs2O6
• Vortex Redistribution below the First-Order Transition Temperature in the β-Pyrochlore Superconductor KOs_2O_6
• Unconventional Superconducting Symmetry in a Checkerboard Antiferromagnet
• Supersolid phases of a doped valence-bond quantum antiferromagnet: Evidence for a coexisting superconducting order parameter
• Microscopic properties of vortex state in YB6 probed by muon spin rotation
• Scanning Tunneling Spectroscopy in the Superconducting State and Vortex Cores of the beta-pyrochlore KOs2O6
• Theoretical study of NMR relaxation due to rattling phonons
• Phonon Dynamics and Multipolar Isomorphic Transition in beta-pyrochlore KOs2O6
• Magnetic and charge transport properties of the Na-based Os oxide pyrochlore
• Large and homogeneous mass enhancement in the rattling-induced superconductor KOs${}_2$O${}_6$
• Quasi-Classical Calculation of the Mixed-State Thermal Conductivity in s-Wave and d-Wave Superconductors