Superconducting properties of heavy fermion UTe revealed by Te-nuclear magnetic resonance
Te核磁気共鳴法により明らかになった重い電子系UTeの超伝導特性
仲嶺 元輝*; 北川 俊作*; 石田 憲二*; 徳永 陽 ; 酒井 宏典 ; 神戸 振作 ; 仲村 愛*; 清水 悠晴*; 本間 佳哉*; Li, D.*; 本多 史憲*; 青木 大*
Nakamine, Genki*; Kitagawa, Shunsaku*; Ishida, Kenji*; Tokunaga, Yo; Sakai, Hironori; Kambe, Shinsaku; Nakamura, Ai*; Shimizu, Yusei*; Homma, Yoshiya*; Li, D.*; Honda, Fuminori*; Aoki, Dai*
We have performed the Te-nuclear magnetic resonance (NMR) measurement in the field along the axis on the newly discovered superconductor UTe, which is a candidate of a spin-triplet superconductor. The nuclear spin-lattice relaxation rate divided by temperature 1/ abruptly decreases below a superconducting (SC) transition temperature without showing a coherence peak, indicative of UTe being an unconventional superconductor. It was found that the temperature dependence of 1/ in the SC state cannot be understood by a single SC gap behavior but can be explained by a two SC gap model. The Knight shift, proportional to the spin susceptibility, decreases below , but the magnitude of the decrease is much smaller than the decrease expected in the spin-singlet pairing. Rather, the small Knight-shift decrease as well as the absence of the Pauli-depairing effect can be interpreted by the spin triplet scenario.