Connection between f-electron correlations and magnetic excitations in UTe₂.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Magnetism

Background:

• Understanding the exotic properties of UTe2, a candidate spin-triplet superconductor, is crucial for advancing quantum materials research.
• Low-energy magnetic excitations play a key role in the superconducting mechanisms of novel materials.

Purpose of the Study:

• To investigate the detailed anisotropic dispersion of magnetic excitations in UTe2.
• To explore the influence of applied magnetic fields on these excitations.
• To elucidate the origin of the observed magnetic excitations.

Main Methods:

• Inelastic neutron scattering was employed to probe the magnetic excitations.
• Experiments were conducted at low temperatures and with applied magnetic fields up to 11 Tesla.
• Analysis of scattering intensity provided insights into the nature of magnetic moments.

Main Results:

• Detailed anisotropic dispersion of low-temperature, low-energy magnetic excitations was revealed.
• Magnetic excitations emerge from the Brillouin zone boundary at Y and T points and disperse along the c-axis.
• Magnetism was found to be field-independent in the (hk0) plane up to 11 T.

Conclusions:

• The scattering intensity suggests U3+/U4+ f-electron spins with preferential orientation along the c-axis.
• A fluctuating magnetic moment of 1.7(5) Bohr magnetons was determined.
• Interband spin excitons from f-electron hybridization are proposed as the origin of magnetic excitations in UTe2.