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Thermodynamics of the quantum easy-plane antiferromagnet on the triangular lattice

L. Capriotti·A. Cuccoli·V. Tognetti·P. Verrucchi·R. Vaia
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Abstract

The classical XXZ triangular-lattice antiferromagnet (TAF) shows both an Ising and a BKT transition, related to the chirality and the in-plane spin components, respectively. In this paper the quantum effects on the thermodynamic quantities are evaluated by means of the pure-quantum self-consistent harmonic approximation (PQSCHA), that allows one to deal with any spin value through classical MC simulations. We report the internal energy, the specific heat, and the in-plane correlation length of the quantum XX0 TAF, for S=1/2, 1, 5/2. The quantum transition temperatures turn out to be smaller the smaller the spin, and agree with the few available theoretical and numerical estimates.

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L. Capriotti, A. Cuccoli, V. Tognetti, P. Verrucchi, R. Vaia. 1999-02-01. Thermodynamics of the quantum easy-plane antiferromagnet on the triangular lattice. https://doi.org/10.1103/physrevb.60.7299

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