Phase diagram and critical behavior of the square-lattice Ising model with competing nearest-neighbor and next-nearest-neighbor interactions.
Using the parallel tempering algorithm and graphics processing unit accelerated techniques, we have performed large-scale Monte Carlo simulations of the Ising model on a square lattice with antiferromagnetic (repulsive) nearest-neighbor and next-nearest-neighbor interactions of the same strength and subject to a uniform magnetic field. Both transitions from the (2x1) and row-shifted (2x2) ordered phases to the paramagnetic phase are continuous. From our data analysis, re-entrance behavior of the (2x1) critical line and a bicritical point which separates the two ordered phases at T=0 are confirmed. Based on the critical exponents we obtained along the phase boundary, Suzuki's weak universality seems to hold.
Yin
Junqi
J
Center for Simulational Physics, University of Georgia, Athens, Georgia 30602, USA.
Landau
D P
DP
D003198:Computer Simulation; D004574:Electromagnetic Fields; D008956:Models, Chemical; D015233:Models, Statistical; D044367:Phase Transition / Q000528:radiation effects*