The recently discovered superconductor UTe2, with a Tc between 1.5~K and 2~K, is attracting much attention due to strong suspicion of spin-triplet and topological superconductivity. Its properties under magnetic field are also remarkable, with field-reinforced and field-induced superconducting phases. Here, we report the first complete thermodynamic determination of the phase diagram for fields applied along the three crystallographic directions. Measurements were performed up to 36~T along the hard magnetisation b~axis in order to follow the superconducting transition up to the metamagnetic transition at Hm=34.75~T. They reveal the existence of a phase transition line within the superconducting phase, and drastic differences occurring between these two phases. Detailed analysis supports a different spin state between the two phases, implying a low-field spin-triplet to high-field spin-singlet transition, a unique case among superconductors, giving insight on the mechanisms leading to spin-triplet superconductivity.
@article{arxiv.2205.04524,
title = {Field-induced tuning of the pairing state in a superconductor},
author = {Adrien Rosuel and Christophe Marcenat and Georg Knebel and Thierry Klein and Alexandre Pourret and Nils Marquardt and Qun Niu and Simon Rousseau and Albin Demuer and Gabriel Seyfarth and Gérard Lapertot and Dai Aoki and Daniel Braithwaite and Jacques Flouquet and Jean-Pascal Brison},
journal= {arXiv preprint arXiv:2205.04524},
year = {2023}
}
Comments
Main paper : 17 pages and 15 figures, supplementary material : 17 pages and 17 figures