Symmetry of magnetic correlations in spin-triplet superconductor UTe₂

The temperature dependence of the low-energy magnetic excitations in the spin-triplet superconductor UTe₂ was measured via inelastic neutron scattering in the normal and superconducting states. These excitations have a peak intensity at 4 meV, follow the Brillouin zone edges near the crystallographic b-axis, obey the paramagnetic structural symmetry, and track the temperature evolution of the heavy fermion bulk magnetic susceptibility. Thus, the imaginary part of the dynamic susceptibility follows the behavior of interband correlations in a hybridized Kondo lattice with an appropriate characteristic energy. These excitations are a lower-dimensional analog of phenomena observed in other Kondo lattice materials, such that their presence is not necessarily due to dominance of ferromagnetic or antiferromagnetic correlations. The onset of superconductivity alters the magnetic excitations noticeably on the same energy scales, suggesting that these changes originate from additional electronic structure modification.

Nicholas P. Butch, Sheng Ran, Shanta R. Saha, Paul M. Neves, Mark P. Zic, Johnpierre Paglione, Sergiy Gladchenko, Qiang Ye, Jose A. Rodriguez-Rivera