Exchange-enhanced paramagnetism amid a flat band inYCo<sub>2</sub>
ORAL
Abstract
Revisiting the large family of cubic AB2 Laves phase materials where the B sublattice forms a pyrochlore network finds examples of correlated electronic and magnetic phases that are worthy of study via a modern approach in terms of flat bands and topology. YCo2 is a cubic-Laves phase exchange-enhanced paramagnet sitting close to a ferromagnetic instability. We present ARPES and DFT results that show a flat electronic band lying ≈ 300 meV below EF, and inelastic neutron scattering (INS) data revealing paramagnons extending past 100 meV which are less damped than for narrow-band Stoner magnets like Pd or Ni3Ga. In addition, we find a striking zone-to-zone momentum dependence of the paramagnon intensity which appears inconsistent with q-independent Stoner theory. We present our analysis of the paramagnons using a diffusive model for the magnetic susceptibility and discuss our analysis of the Brillouin-zone dependent variation of INS intensity.
*Work at the Ames Laboratory was supported by the Department of Energy, Basic Energy Sciences under Contract No. DE-AC02-07CH11358. A portion of this research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. The beam time was allocated to ARCS on proposal number IPTS-22249 and to TOPAZ on proposal number IPTS-25682. Work at Rice University (AH, SL, EM) was supported by the Robert A. Welch Foundation Grant No. C-2114.
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Presenters
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Benjamin G. Ueland
- Ames National Laboratory