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arXiv · 2307.10724

Longitudinal spin fluctuations driving field-reinforced superconductivity in UTe$_2$

Yo Tokunaga·Hironori Sakai·Shinsaku Kambe·Petr Opletal·Yoshifumi Tokiwa·Yoshinori Haga·Shunsaku Kitagawa·Kenji Ishida·Dai Aoki·Georg Knebel·Gerard Lapertot·Steffen Krämer·Mladen Horvatić
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Abstract

Our measurements of $^{125}$Te NMR relaxations reveal an enhancement of electronic spin fluctuations above $\mu_0H^*\sim15$ T, leading to their divergence in the vicinity of the metamagnetic transition at $\mu_0H_m\approx35$ T, below which field-reinforced superconductivity appears when a magnetic field ($H$) is applied along the crystallographic $b$ axis. The NMR data evidence that these fluctuations are dominantly longitudinal, providing a key to understanding the peculiar superconducting phase diagram in $H\|b$, where such fluctuations enhance the pairing interactions.

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Yo Tokunaga, Hironori Sakai, Shinsaku Kambe, Petr Opletal, Yoshifumi Tokiwa, Yoshinori Haga, Shunsaku Kitagawa, Kenji Ishida, Dai Aoki, Georg Knebel, Gerard Lapertot, Steffen Krämer, Mladen Horvatić. 2023-07-20. Longitudinal spin fluctuations driving field-reinforced superconductivity in UTe$_2$. https://doi.org/10.1103/physrevlett.131.226503

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