Confinement of fractional excitations in a triangular lattice antiferromagnet

Abstract

High-resolution neutron and THz spectroscopies are used to study the magnetic excitation spectrum of Cs${}_2$CoBr${}_4$, a distorted-triangular-lattice antiferromagnet with nearly XY-type anisotropy. What was previously thought of as a broad excitation continuum [Phys. Rev. Lett. 129, 087201 (2022)] is shown to be a series of dispersive bound states reminiscent of "Zeeman ladders" in quasi-one-dimensional Ising systems. At wave vectors where inter-chain interactions cancel at the Mean Field level, they can indeed be interpreted as bound finite-width kinks in individual chains. Elsewhere in the Brillouin zone their true two-dimensional structure and propagation are revealed.

11 pages, 8 figures

References in corpus (7)

• Mantid - Data Analysis and Visualization Package for Neutron Scattering and $\mu SR$ Experiments
• Models and Materials for Generalized Kitaev Magnetism
• Energy spectrum of bound-spinons in the quantum Ising spin-chain ferromagnet
• Experimental Observation of Quantum Many-Body Excitations of $E_8$ Symmetry in the Ising Chain Ferromagnet CoNb${}_2$O${}_6$
• Evidence of Two-Spinon Bound States in the Magnetic Spectrum of Ba${}_3$CoSb${}_2$O${}_9$
• Spin Density Wave versus Fractional Magnetization Plateau in a Triangular Antiferromagnet
• Breakdown of Linear Spin-wave Theory and Existence of Spinon Bound States in the Frustrated Kagome Lattice Antiferromagnet

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• Competing states in the $S=1/2$ triangular-lattice $J_1$-$J_2$ Heisenberg model: a dynamical density-matrix renormalization group study