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Dynamical Properties of a Haldane Gap Antiferromagnet

O. Golinelli·Th. Jolicoeur·R. Lacaze
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Abstract

We study the dynamic spin correlation function of a spin one antiferromagnetic chain with easy-plane single-ion anisotropy. We use exact diagonalization by the Lancz\H os method for chains of lengths up to N=16 spins. We show that a single-mode approximation is an excellent description of the dynamical properties. A variational calculation allows us to clarify the nature of the excitations. The existence of a two-particle continuum near zero wavevector is clearly seen both in finite-size effects and in the dynamical structure factor. The recent neutron scattering experiments on the quasi-one-dimensional antiferromagnet NENP are fully explained by our results.

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O. Golinelli, Th. Jolicoeur, R. Lacaze. 1992-12-09. Dynamical Properties of a Haldane Gap Antiferromagnet. https://doi.org/10.1088/0953-8984%2F5%2F9%2F024

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