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arXiv · 2307.15784

Superconducting-Spin Reorientation in Spin-Triplet Multiple Superconducting Phases of UTe2

Katsuki Kinjo·Hiroki Fujibayashi·Hiroki Matsumura·Fumiya Hori·Shunsaku Kitagawa·Kenji Ishida·Yo Tokunaga·Hironori Sakai·Shinsaku Kambe·Ai Nakamura·Yusei Shimizu·Yoshiya Homma·Dexin Li·Fuminori Honda·Dai Aoki
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Abstract

Superconducting (SC) state has spin and orbital degrees of freedom, and spin-triplet superconductivity shows multiple SC phases due to the presence of these degrees of freedom. However, the observation of spin-direction rotation occurring inside the SC state (SC spin rotation) has hardly been reported. UTe2, a recently discovered topological superconductor, exhibits various SC phases under pressure: SC state at ambient pressure (SC1), high-temperature SC state above 0.5 GPa (SC2), and low-temperature SC state above 0.5 GPa (SC3). We performed nuclear magnetic resonance and AC susceptibility measurements on single-crystal UTe2. The b-axis spin susceptibility remains unchanged in SC2, unlike in SC1, and decreases below the SC2-SC3 transition with spin modulation. These unique properties in SC3 arise from the coexistence of two SC order parameters. Our NMR results confirm the spin-triplet superconductivity with SC spin parallel to b in SC2, and unveil the remaining of spin degrees of freedom in superconducting UTe2.

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Katsuki Kinjo, Hiroki Fujibayashi, Hiroki Matsumura, Fumiya Hori, Shunsaku Kitagawa, Kenji Ishida, Yo Tokunaga, Hironori Sakai, Shinsaku Kambe, Ai Nakamura, Yusei Shimizu, Yoshiya Homma, Dexin Li, Fuminori Honda, Dai Aoki. 2023-07-28. Superconducting-Spin Reorientation in Spin-Triplet Multiple Superconducting Phases of UTe2. https://doi.org/10.1126/sciadv.adg2736

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