Anisotropic response of spin susceptibility in the superconducting state of UTe probed with Te-NMR measurement

Nakamine, Genki*; Kinjo, Katsuki*; Kitagawa, Shunsaku*; Ishida, Kenji*; Tokunaga, Yo  ; Sakai, Hironori   ; Kambe, Shinsaku  ; Nakamura, Ai*; Shimizu, Yusei*; Homma, Yoshiya*; Li, D.*; Honda, Fuminori*; Aoki, Dai*

To investigate spin susceptibility in a superconducting (SC) state, we measured the Te-NMR Knight shifts at magnetic fields () up to 6.5 T along the and axes of single-crystal UTe, a promising candidate for a spin-triplet superconductor. In the SC state, the Knight shifts along the and axes ( and , respectively) decreased slightly, and the decrease in was almost constant up to 6.5 T. The reduction in decreased with increasing , and was unchanged through the SC transition temperature at 5.5 T, excluding the possibility of spin-singlet pairing. Our results indicate that spin susceptibilities along the and axes slightly decrease in the SC state in low , and the response of SC spin susceptibility is anisotropic on the plane.