We investigate the effect of easy-axis metamagnetic crossover on superconductivity in UTe2 along the a-axis through measurements of AC susceptibility, magnetization, and the magnetocaloric effect. In ultra-clean single crystals, we identify a field-induced phase transition within the superconducting state at 5.6 T, driven by metamagnetism. This transition leads to a high-field superconducting state, significantly increasing the upper critical field to 12 T. A sudden increase in entropy at the transition suggests a self-reconstruction of the order parameter, enabling multi-component superconducting states to adapt to external perturbations.
@article{arxiv.2210.11769,
title = {Self-reconstruction of order parameter in spin-triplet superconductor UTe$_2$},
author = {Y. Tokiwa and P. Opletal and H. Sakai and K. Kubo and S. Kambe and E. Yamamoto and M. Kimata and S. Awaji and T. Sasaki and D. Aoki and Y. Yanase and Y. Tokunaga and Y. Haga},
journal= {arXiv preprint arXiv:2210.11769},
year = {2025}
}