Connection between f-electron correlations and magnetic excitations in UTe₂

The detailed anisotropic dispersion of the low-temperature, low-energy magnetic excitations of the candidate spin-triplet superconductor UTe₂ is revealed using inelastic neutron scattering. The magnetic excitations emerge from the Brillouin zone boundary at the high symmetry Y and T points and disperse along the crystallographic $$ -axis. In applied magnetic fields to at least μ ₀ H = 11 T along the $$ , the magnetism is found to be field-independent in the (h k0) plane. The scattering intensity is consistent with that expected from U³⁺/U⁴⁺ f-electron spins with preferential orientation along the crystallographic $$ -axis, and a fluctuating magnetic moment of μ =1.7(5) μ . We propose interband spin excitons arising from f-electron hybridization as a possible origin of the magnetic excitations in UTe₂.