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BIBTEX RIS

From an antiferromagnet to a valence bond solid: evidence for a first-order phase transition

2008; Institute of Physics; Volume: 2008; Issue: 02 Linguagem: Inglês

10.1088/1742-5468/2008/02/p02009

ISSN

1742-5468

Autores

Fu-Jiun Jiang, Matthias Nyfeler, Shailesh Chandrasekharan, U-J Wiese,

Tópico(s)

Theoretical and Computational Physics

Resumo

Using a loop–cluster algorithm we investigate the spin- Heisenberg antiferromagnet on a square lattice with exchange coupling J and an additional four-spin interaction of strength Q. We confirm the existence of a phase transition separating antiferromagnetism at J/Q>Jc/Q from a valence bond solid (VBS) state at J/Q Jc/Q the staggered magnetization, the spin stiffness and the spinwave velocity of the antiferromagnet are determined by fitting Monte Carlo data to analytic results from the systematic low-energy effective field theory for magnons. Finally, we also investigate the physics of the VBS state at J/Q<Jc/Q and we show that long but finite antiferromagnetic correlations are still present.

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