paper

Monte Carlo studies of the Ising square lattice with competing interactions

arXiv:0809.2503 · doi:10.1088/1742-6596/145/1/012051

Abstract

We use improved Monte-Carlo algorithms to study the antiferromagnetic 2D-Ising model with competing interactions $J_{1}$ on nearest neighbour and $J_{2}$ on next-nearest neighbour bonds. The finite-temperature phase diagram is divided by a critical point at $J_{2} = J_{1} /2$ where the groundstate is highly degenerate. To analyse the phase boundaries we look at the specific heat and the energy distribution for various ratios of $J_{2} / J_{1}$ . We find a first order transition for small $J_{2} > J_{1} /2$ and the transition temperature suppressed to $T_{C} = 0$ at the critical point.

4 pages, 4 figures, accepted for publication in the proceedings of the conference on Highly Frustrated Magnets 2008 in Braunschweig