TY  - JOUR
PB  - SciPost Foundation
DO  - 10.21468/SciPostPhys.16.6.151
TI  - Free energy and metastable states in the square-lattice $J_1$-$J_2$ Ising model
PY  - 2024/06/06
UR  - https://scipost.org/SciPostPhys.16.6.151
JF  - SciPost Physics
JA  - SciPost Phys.
VL  - 16
IS  - 6
SP  - 151
A1  - Abalmasov, Veniamin
AB  - Free energy as a function of polarization is calculated for the square-lattice $J_1$-$J_2$ Ising model for $J_2 < |J_1|/2$ using the random local field approximation (RLFA) and Monte Carlo (MC) simulations. Within RLFA, it reveals a metastable state with zero polarization in the ordered phase. In addition, the Landau free energy calculated within RLFA indicates a geometric slab-droplet phase transition at low temperature, which cannot be predicted by the mean field approximation. In turn, restricted free energy calculations for finite-size samples, exact and using MC simulations, reveal metastable states with a wide range of polarization values, but with only two domains. Taking into account the dependence of the restricted free energy on the nearest-neighbor correlations allows us to identify several more metastable states. The calculations also reveal additional slab-droplet transitions at $J_2 > |J_1|/4$. These findings enrich our knowledge of the $J_1$-$J_2$ Ising model and the RLFA as a useful theoretical tool to study phase transitions in spin systems.
ER  -

@Article{10.21468/SciPostPhys.16.6.151,
	title={{Free energy and metastable states in the square-lattice $J_1$-$J_2$ Ising model}},
	author={Veniamin A. Abalmasov},
	journal={SciPost Phys.},
	volume={16},
	pages={151},
	year={2024},
	publisher={SciPost},
	doi={10.21468/SciPostPhys.16.6.151},
	url={https://scipost.org/10.21468/SciPostPhys.16.6.151},
}