Exotic superconducting properties in the electron-hole-compensated heavy-fermion "semimetal" URuSi

笠原 裕一*; 岩澤 卓矢*; 宍戸 寛明*; 芝内 孝禎*; Behnia, K.*; 芳賀 芳範; 松田 達磨; 大貫 惇睦; Sigrist, M.*; 松田 祐司*

Physical Review Letters, 99(116), p.116402_1 - 116402_4, 2007/09

https://doi.org/10.1103/PhysRevLett.99.116402

We show that the charge and thermal transport measurements on ultraclean crystals of URuSi reveal a number of unprecedented superconducting properties. The uniqueness is best highlighted by the peculiar field dependence of thermal conductivity including the first order transition at with a reduction of entropy flow. This is a consequence of multi-band superconductivity with compensated electronic structure in the hidden order state of this system. We provide strong evidence for a new type of unconventional superconductivity with two distinct gaps having different nodal topology.