Gap structure and exotic superconducting state of URu2Si 2

Abstract

The heavy-fermion compound URu2Si2 has mystified researchers since the superconducting state coexists with enigmatic "hidden order" phase. In order to elucidate the superconducting gap function of URu2Si2, we performed the thermal transport measurements at low temperatures on ultraclean single crystals of URu2Si 2. The results provide strong evidence for a new type of unconventional superconducting state, having two distinct gaps with different nodal topologies. We propose a gap function with chiral d-wave form Δk ∝ kz(kx ± iky). © 2009 IOP Publishing Ltd.