Author(s): Michal Vališka, Tetiana Haidamak, Andrej Cabala, Petr Proschek, Vladimír Sechovský, Andreas Hauspurg, and Sergei Zherlitsyn We report ultrasound velocity measurements on an ultraclean ${\mathrm{UTe}}_{2}$ single crystal with ${T}_{c}>2\text{ }\text{ }\mathrm{K}$ for $H∥b$, performed up to 18 T and down to 0.33 K. The measurements provide the missing bulk thermodynamic evidence for an additional high-field phase bounda… [Phys. Rev. Lett. 137, 126003] Published Tue Sep 15, 2026