Tricritical point of J1-J2 Ising model on hyperbolic lattice
Abstract
A ferromagnetic-paramagnetic phase transition of the two-dimensional frustrated Ising model on a hyperbolic lattice is investigated by use of the corner transfer matrix renormalization group method. The model contains ferromagnetic nearest-neighbor interaction J1 and the competing antiferromagnetic interaction J2. A mean-field like second-order phase transition is observed when the ratio = J2 / J1 is less than 0.203. In the region 0.203 < < 1/4, the spontaneous magnetization is discontinuous at the transition temperature. Such tricritical behavior suggests that the phase transitions on hyperbolic lattices need not always be mean-field like.
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