Three-Magnon Bound State in the Quasi-1d Antiferromagnet α-NaMnO2

October 5, 2020
Three-Magnon Bound State in the Quasi-1d  Antiferromagnet α-NaMnO2
(a) Measured excitation spectrum of α-NaMnO2 and (b) cuts through the antiferromagnetic zone center (white dashed line in (a)) demonstrating the observation n=1, n=2, and n=3 magnon modes.

Scientific Achievement

A three-magnon bound state is observed in the quasi-1d antiferromagnet α-NaMnO2 and can be described by a semiclassical theory that maps the excitations onto a few-body droplet model of interacting bosons.

Significance and Impact

This work establishes a strong analogy between the physics of interacting magnons in antiferromagnets with uniaxial anisotropy and interacting bosons typically studied via ultracold atoms experiments. 

Research Details

  • The magnetic excitation spectrum was measured with inelastic neutron scattering, with the observation of single magnons as well as two and three-magnon bound states.
  • The results were well-described by a semi-classical theory with spectral functions calculated using density matrix renormalization group and time evolution calculations.


“Three-Magnon Bound State in the Quasi-One-Dimensional Antiferromagnet α-NaMnO2”
Rebecca L. Dally, Alvin J. R. Heng, Anna Keselman, Mitchell M. Bordelon, Matthew B. Stone, Leon Balents, and Stephen D. Wilson, 
Physical Review Letters, 124, 197203 (2020).