Speaker
Description
Due to its potentially spin-triplet-superconducting ground state, UTe$_2$ has triggered a wave of enthusiasm among condensed-matter researchers since the discovery of superconductivity below $1.6\,$K in this anisotropic heavy-fermion paramagnet. As the quality of single crystals improved, e.g., $T_c$ was pushed to $2.1\,$K, some of the fog about UTe$_2$’s mysterious properties has cleared. Nevertheless, the excitement has only become stronger, as UTe$_2$ exhibits signatures of multiple superconducting phases with distinct order parameters stabilized by different tuning parameters, such as pressure, magnetic field, or field orientation. Particularly, strong magnetic fields applied to UTe$_2$ appear to not only suppress superconductivity, as expected for a textbook superconductor, but also enhance and enable additional phases in a rare and very unconventional phase diagram. In this talk, I will providea brief overview on UTe$_2$’s high-field properties and review recent results concerned with the field-induced superconducting phases in this special compound. In particular, I will focus on what is known so far about the reentrant superconductivity that sets in for particular field orientations at field values beyond approximately $40\,$T. Latest results from experiments in fields up to $70\,$T have certain implication to the possible origin of the extremely field-robust reentrant superconductivity in UTe$_2$.
[1] T. Helm et al., Nat. Commun. 15, 37 (2024)
[2] F. Husstedt et al., Phys. Rev. B 111, 235131 (2025)
