Magnetic excitations in the topological semimetal ${\mathrm{YbMnSb}}_2$

Abstract

We report neutron scattering measurements on YbMnSb${}_2$ which shed new light on the nature of the magnetic moments and their interaction with Dirac fermions. Using half-polarized neutron diffraction we measured the field-induced magnetization distribution in the paramagnetic phase and found that the magnetic moments are well localised on the Mn atoms. Using triple-axis neutron scattering we measured the magnon spectrum throughout the Brillouin zone in the antiferromagnetically ordered phase, and we determined the dominant exchange interactions from linear spin-wave theory. The analysis shows that the interlayer exchange is five times larger than in several related compounds containing Bi instead of Sb. We argue that the coupling between the Mn local magnetic moments and the topological band states is more important in YbMnSb${}_2$ than in the Bi compounds.

arXiv comment8 pages, 8 figures. Submitted to Physical Review B

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Cited by in corpus (2)

• Coupling of magnetism and Dirac fermions in YbMnSb2
• Spin waves in Dirac semimetal Ca${}_{0.6}$Sr${}_{0.4}$MnSb${}_2$ investigated with neutrons by the diffraction method