Correlated cluster mean-field theory for Ising-like spin systems

Abstract

The correlated cluster mean-field (CCMF) theory is an approximative method that have been applied to the study of spin-1∕2 Hamiltonians, providing accurate results for several magnetic systems. In this paper, we review the method applications and extend its framework to the study of Ising-like systems with spin S>1∕2. Our investigation of the spin-1 ferromagnet on honeycomb, square and simple cubic lattices showed that the CCMF method results can be compared to state-of-the-art methods. We also present the method application for higher spin (3∕2≤S≤5∕2) and mixed-spin systems on the honeycomb lattice, comparing our findings with other techniques. As a result, the reduced critical temperature obtained within the CCMF theory overestimates by only 5% the exact result for the mixed spin-(1,1∕2) system.