Angle Resolved Thermal Conductivity of Superconducting CeCoIn$_{5}$ along the Nodal Direction
ORAL
Abstract
The thermal conductivity measurement in a rotating magnetic field is a powerful probe of the structure of the superconducting energy gap. The four-fold oscillation in thermal conductivity of CeCoIn$_{5}$, with the heat current in the anti-nodal direction, has revealed the d-wave nature of its order parameter. We have measured the thermal conductivity with the heat current along the [110] (nodal) direction and the magnetic field rotating in the \textit{ab}-plane. In contrast to the smooth oscillation found with the heat current along the anti-nodal direction, a sharp increase of thermal conductivity was observed when the magnetic field is also in the [110] direction, parallel to the heat current. This suggests that the scattering of the nodal quasiparticle is strongly suppressed along the magnetic field direction. In addition, a smaller increase of the thermal conductivity was observed when the magnetic field is approximately 30 degree away from the nodal direction, perhaps due to a Fermi surface anomaly.
*Work at Los Alamos was performed under the auspices of the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering.
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