Instabilities of heavy magnons in an anisotropic magnet

Xiaojian Bai; Shang-Shun Zhang; Hao Zhang; Zhiling Dun; W Adam Phelan; V Ovidiu Garlea; Martin Mourigal; Cristian D Batista

doi:10.1038/s41467-023-39940-1

Instabilities of heavy magnons in an anisotropic magnet

Nat Commun. 2023 Jul 14;14(1):4199. doi: 10.1038/s41467-023-39940-1.

Authors

Xiaojian Bai^#^{1

2

3}, Shang-Shun Zhang^#⁴, Hao Zhang^{5

6}, Zhiling Dun⁷, W Adam Phelan⁸, V Ovidiu Garlea⁹, Martin Mourigal⁷, Cristian D Batista^{5

10}

Affiliations

¹ Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA. xbai@lsu.edu.
² School of Physics, Georgia Institute of Technology, Atlanta, GA, 30332, USA. xbai@lsu.edu.
³ Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA, 70803, USA. xbai@lsu.edu.
⁴ Department of Physics and Astronomy, University of Tennessee, Knoxville, TN, 37996, USA. shangshun89@gmail.com.
⁵ Department of Physics and Astronomy, University of Tennessee, Knoxville, TN, 37996, USA.
⁶ Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
⁷ School of Physics, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
⁸ PARADIM, Department of Chemistry, The Johns Hopkins University, Baltimore, 21218, MD, USA.
⁹ Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
¹⁰ Neutron Scattering Division and Shull-Wollan Center, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.

^# Contributed equally.

Abstract

The search for new elementary particles is one of the most basic pursuits in physics, spanning from subatomic physics to quantum materials. Magnons are the ubiquitous elementary quasiparticle to describe the excitations of fully-ordered magnetic systems. But other possibilities exist, including fractional and multipolar excitations. Here, we demonstrate that strong quantum interactions exist between three flavors of elementary quasiparticles in the uniaxial spin-one magnet FeI₂. Using neutron scattering in an applied magnetic field, we observe spontaneous decay between conventional and heavy magnons and the recombination of these quasiparticles into a super-heavy bound-state. Akin to other contemporary problems in quantum materials, the microscopic origin for unusual physics in FeI₂ is the quasi-flat nature of excitation bands and the presence of Kitaev anisotropic magnetic exchange interactions.

MeSH terms

Anisotropy
Magnetic Fields*
Magnets*
Neutrons
Physics

Abstract

MeSH terms

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