Breakdown of Linear Spin-wave Theory and Existence of Spinon Bound States in the Frustrated Kagome Lattice Antiferromagnet

Abstract

Spin dynamics of the spin-1/2 kagome lattice antiferromagnet Cs${}_2$Cu${}_3$SnF${}_{12}$ was studied using high-resolution, time-of-flight inelastic neutron scattering. The flat mode, a characteristic of the frustrated kagome antiferromagnet, and the low-energy dispersive mode, which is dominated by magnons, can be well described by the linear spin-wave theory. However, the theory fails to describe three weakly dispersive modes between 9 and 14 meV. These modes could be attributed to two-spinon bound states, which decay into free spinons away from the zone center and at a high temperature, giving rise to continuum scattering.

4 figures and Supplementary Information

References in corpus (11)

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Cited by in corpus (3)

• Topological Hybrids of Magnons and Magnon Bound Pairs
• Confinement of fractional excitations in a triangular lattice antiferromagnet
• A Series Expansion Study for Large Negative Quantum Renormalization of Magnon Spectra in the $S=1/2$ Kagome-Lattice Heisenberg Antiferromagnet Cs${}_2$Cu${}_3$SnF${}_{12}$