Connection between f-electron correlations and magnetic excitations in UTe2

Thomas Halloran; Peter Czajka; Gicela Saucedo Salas; Corey E Frank; Chang-Jong Kang; J A Rodriguez-Rivera; Jakob Lass; Daniel G Mazzone; Marc Janoschek; Gabriel Kotliar; Nicholas P Butch

doi:10.1038/s41535-024-00720-9

Connection between f-electron correlations and magnetic excitations in UTe₂

NPJ Quantum Mater. 2025;10(1):2. doi: 10.1038/s41535-024-00720-9. Epub 2025 Jan 4.

Authors

Thomas Halloran^{1

2}, Peter Czajka^{1

2}, Gicela Saucedo Salas^{1

2}, Corey E Frank^{1

2}, Chang-Jong Kang³, J A Rodriguez-Rivera^{1

4}, Jakob Lass^{5

6}, Daniel G Mazzone⁵, Marc Janoschek^{7

8}, Gabriel Kotliar^{9

10}, Nicholas P Butch^{1

2}

Affiliations

¹ NIST Center for Neutron Research, Gaithersburg, MD 20899 USA.
² Department of Physics and Astronomy, University of Maryland, College Park, USA.
³ Department of Physics, Chungnam National University, Daejeon, 34134 Korea.
⁴ Department of Materials Science, University of Maryland, College Park, MD 20742 USA.
⁵ Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, CH-5232, Villigen PSI Switzerland.
⁶ Laboratory for Quantum Magnetism, Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
⁷ Laboratory for Neutron and Muon Instrumentation, PSI Center for Neutron and Muon Sciences, Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland.
⁸ Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland.
⁹ Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854 USA.
¹⁰ Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973 USA.

Abstract

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 $\hat{b}$ -axis. In applied magnetic fields to at least μ ₀ H = 11 T along the $\hat{c} - axis$ , 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 $\hat{a}$ -axis, and a fluctuating magnetic moment of μ _{e f f} =1.7(5) μ _B . We propose interband spin excitons arising from f-electron hybridization as a possible origin of the magnetic excitations in UTe₂.

Keywords: Magnetic properties and materials; Superconducting properties and materials.