Giant transverse magnetic fluctuations at the edge of re-entrant superconductivity in UTe$_{2}$

Fuente: arXiv
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Hauptverfasser: Zambra, Valeska, Nathwani, Amit, Nauman, Muhammad, Lewin, Sylvia K., Frank, Corey E., Butch, Nicholas P., Shekhter, Arkady, Ramshaw, B. J., Modic, K. A.
Format: Preprint
Veröffentlicht: 2025
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author Zambra, Valeska
Nathwani, Amit
Nauman, Muhammad
Lewin, Sylvia K.
Frank, Corey E.
Butch, Nicholas P.
Shekhter, Arkady
Ramshaw, B. J.
Modic, K. A.
author_facet Zambra, Valeska
Nathwani, Amit
Nauman, Muhammad
Lewin, Sylvia K.
Frank, Corey E.
Butch, Nicholas P.
Shekhter, Arkady
Ramshaw, B. J.
Modic, K. A.
contents UTe$_{2}$ exhibits the remarkable phenomenon of re-entrant superconductivity, whereby the zero-resistance state reappears above 40 tesla after being suppressed with a field of around 10 tesla. One potential pairing mechanism, invoked in the related re-entrant superconductors UCoGe and URhGe, involves transverse fluctuations of a ferromagnetic order parameter. However, the requisite ferromagnetic order - present in both UCoGe and URhGe - is absent in UTe$_{2}$, and magnetization measurements show no sign of strong fluctuations. Here, we measure the magnetotropic susceptibility of UTe$_{2}$ across two field-angle planes. This quantity is sensitive to the magnetic susceptibility in a direction transverse to the applied magnetic field - a quantity that is not accessed in conventional magnetization measurements. We observe a very large decrease in the magnetotropic susceptibility over a broad range of field orientations, indicating a large increase in the transverse magnetic susceptibility. The three superconducting phases of UTe$_{2}$, including the high-field re-entrant phase, surround this region of enhanced susceptibility in the field-angle phase diagram. The strongest transverse susceptibility is found near the critical end point of the high-field metamagnetic transition, suggesting that quantum critical fluctuations of a field-induced magnetic order parameter may be responsible for the large transverse susceptibility, and may provide a pairing mechanism for field-induced superconductivity in UTe$_{2}$.
format Preprint
id arxiv_https___arxiv_org_abs_2506_08984
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Giant transverse magnetic fluctuations at the edge of re-entrant superconductivity in UTe$_{2}$
Zambra, Valeska
Nathwani, Amit
Nauman, Muhammad
Lewin, Sylvia K.
Frank, Corey E.
Butch, Nicholas P.
Shekhter, Arkady
Ramshaw, B. J.
Modic, K. A.
Strongly Correlated Electrons
Superconductivity
UTe$_{2}$ exhibits the remarkable phenomenon of re-entrant superconductivity, whereby the zero-resistance state reappears above 40 tesla after being suppressed with a field of around 10 tesla. One potential pairing mechanism, invoked in the related re-entrant superconductors UCoGe and URhGe, involves transverse fluctuations of a ferromagnetic order parameter. However, the requisite ferromagnetic order - present in both UCoGe and URhGe - is absent in UTe$_{2}$, and magnetization measurements show no sign of strong fluctuations. Here, we measure the magnetotropic susceptibility of UTe$_{2}$ across two field-angle planes. This quantity is sensitive to the magnetic susceptibility in a direction transverse to the applied magnetic field - a quantity that is not accessed in conventional magnetization measurements. We observe a very large decrease in the magnetotropic susceptibility over a broad range of field orientations, indicating a large increase in the transverse magnetic susceptibility. The three superconducting phases of UTe$_{2}$, including the high-field re-entrant phase, surround this region of enhanced susceptibility in the field-angle phase diagram. The strongest transverse susceptibility is found near the critical end point of the high-field metamagnetic transition, suggesting that quantum critical fluctuations of a field-induced magnetic order parameter may be responsible for the large transverse susceptibility, and may provide a pairing mechanism for field-induced superconductivity in UTe$_{2}$.
title Giant transverse magnetic fluctuations at the edge of re-entrant superconductivity in UTe$_{2}$
topic Strongly Correlated Electrons
Superconductivity
url https://arxiv.org/abs/2506.08984