Thermal conductivity in the vortex state of the superconductor UPd₂Al₃

The magneto-thermal conductivity κ is calculated for the vortex state of UPd₂Al₃ by assuming horizontal gap nodes. The Green’s function method we employed takes into account the effects of supercurrent flow and Andreev scattering on the quasiparticles due to Abrikosov’s vortex lattice order parameter. The calculated angular dependence of κ_yy for field rotation θ₀ in the ac plane depends strongly on field strength H, impurity scattering, anisotropy of the Fermi velocity, and temperature. For finite temperatures and the clean unitary scattering limit we get qualitative agreement with recent experiments for all four proposed gap functions having horizontal line nodes at ck_z=0, ±π∕4, and ±π∕2.