Normal Fermi Surface in the Nodal Superconductor CeCoIn${}_5$ Revealed via Thermal Conductivity

Abstract

The thermal conductivity of heavy-fermion superconductor CeCoIn${}_5$ was measured with a magnetic field rotating in the tetragonal a-b plane, with the heat current in the anti-nodal direction, $J$ || [100]. We observe a sharp resonance in thermal conductivity for the magnetic field at an angle $\theta$ $\sim$ 12${}^{\circ }$, measured from the heat current direction [100]. This resonance corresponds to the reported resonance at an angle ${\theta }^{\prime }$ $\sim$ 33${}^{\circ }$ from the direction of the heat current applied along the nodal direction, $J$ || [110]. Both resonances, therefore, occur when the magnetic field is applied in the same crystallographic orientation in the two experiments, regardless of the direction of the heat current, proving conclusively that these resonances are due to the structure of the Fermi surface of CeCoIn${}_5$. We argue that the uncondensed Landau quasiparticles, emerging with field, are responsible for the observed resonance. We support our experimental results with density-functional-theory model calculations of the density of states in a rotating magnetic field. Our calculations, using a model Fermi surface of CeCoIn${}_5$, reveal several sharp peaks as a function of the field direction. Our study demonstrates that the thermal-conductivity measurement in rotating magnetic field can probe the normal parts of the Fermi surface deep inside the superconducting state.

References in corpus (14)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Angular Position of Nodes in the Superconducting Gap of Quasi-2D Heavy-Fermion Superconductor CeCoIn_5
• Unconventional superconductivity in CeIrIn${}_5$ and CeCoIn${}_5$: Specific heat and thermal conductivity studies
• Observation of Direct CP Violation in K_{S,L} to ππDecays
• Numerical extraction of de Haas - van Alphen frequencies from calculated band energies
• Nodal Structure of Unconventional Superconductors Probed by the Angle Resolved Thermal Transport Measurements
• Anisotropic thermodynamics of d-wave superconductors in the vortex state
• Unpaired Electrons in the Heavy-Fermion Superconductor CeCoIn_{5}
• Heat transport as a probe of superconducting gap structure
• Unconventional superconductors under rotating magnetic field I: density of states and specific heat
• Intertwined Orders in Heavy-Fermion Superconductor CeCoIn${}_5$
• Unconventional superconductors under rotating magnetic field II: thermal transport
• Ground state, collective mode, phase soliton and vortex in multiband superconductors
• Vortex lattice studies in CeCoIn5 with H perpendicular to c