Gap symmetry and thermal conductivity in nodal superconductors

There are now many nodal superconductors in heavy-fermion (HF) systems, charge-conjugated organic metals, high-Tc cuprates and ruthenates. On the other hand, only few of them have well established Δ(k). We present here a study of the angular-dependent thermal conductivity in the vortex state of some of the nodal superconductors. We hope it will help to identify the nodal directions in Δ(k) of UPd2Al3, UNi2Al3, UBe13 and URu2Si2.