Understanding the chemistry of UTe2 
 

A team of researchers from MPI CPfS has uncovered why the unconventional superconductor UTe₂ exhibits such striking variations in its behavior from sample to sample.

A team of researchers from MPI CPfS has uncovered why the unconventional superconductor UTe₂ exhibits such striking variations in its behavior from sample to sample. While UTe₂ has been the subject of intense study since its discovery, the origin of its inconsistent superconducting properties has remained elusive. By systematically analyzing crystals produced through different synthesis routes, the scientists identified that samples showing one versus two superconducting transitions differ due to local deviations from the translational symmetry, with distinct features observed in the bc plane of the crystal. The study also revealed that even a small number of uranium vacancies – around four percent – can drastically alter the material’s superconducting characteristics. These vacancies cause subtle but measurable changes in the crystal lattice, including a 0.51% difference in unit cell volume, which directly affects whether UTe₂ becomes superconducting.

These findings highlight the extraordinary sensitivity of UTe₂ to minor structural features, reinforcing its unconventional nature and significance in the broader field of superconductivity. By combining advanced chemical and physical analysis, the work provides crucial insights into the interplay between crystal structure and exotic quantum phenomena, paving the way for deeper understanding of strongly correlated materials.