The frustrated Ising model on the body-centered cubic lattice

Abstract

We investigate phase transitions and thermodynamics of the Ising model with first-neighbor (J1) and second-neighbor (J2) antiferromagetic (AF) interactions on the body-centered cubic (bcc) lattice within a cluster mean-field approach. In this lattice, tuning g=J2/J1 leads to a ground-state transition between AF and superantiferromagnetic (SAF) phases at the maximum of frustration g=2/3. Although the ordering temperature is reduced as g→2/3, our findings suggest the absence of strong frustration effects on the model, in good agreement with Monte Carlo simulations. We also find first-order phase transitions between AF and SAF phases at finite temperatures. Furthermore, the cluster mean-field outcomes support a scenario with only continuous phase transitions between the paramagnetic state and the low-temperature long-range orders. Therefore, our results indicate that frustration is unable to change the nature of the order–disorder phase transitions, which can be ascribed to the higher dimensionality of the bcc lattice.