Blume-Emery-Griffiths model on the square lattice with repulsive biquadratic coupling
Abstract
Using a real-space renormalization group procedure with no adjustable parameters, we investigate the Blume-Emery-Griffiths model on the square lattice. The formalism respects sublattice symmetry, allowing the study of both signs of K, the biquadratic exchange coupling. Our results for K>0 are compared with other renormalization group calculations and with exact results, in order to assess the magnitude of the errors introduced by our approximate calculation. The quantitative agreement is excellent; values for critical parameters differ, in some cases, by less than 1% from exact ones. For K<0, our results lead to a rich phase diagram, with antiquadrupolar and ferromagnetic ordered phases. Contrarily to Monte Carlo simulations, these two phases meet only at zero temperature. Both antiquadrupolar-disordered and ferromagnetic-disordered transitions are found to be continuous and no ferrimagnetic phase is found.
Keywords
Cite
@article{arxiv.cond-mat/9611159,
title = {Blume-Emery-Griffiths model on the square lattice with repulsive biquadratic coupling},
author = {N. S. Branco},
journal= {arXiv preprint arXiv:cond-mat/9611159},
year = {2015}
}
Comments
14 pages, plain latex, 5 figures available upon request to [email protected]