First-order phase transitions in the Ising square lattice with first- and second-neighbor interactions Article uri icon

abstract

  • The phase diagram of the Ising square lattice with first- and second-nearest-neighbor antiferromagnetic interactions (J1 and J2) is calculated within the framework of the cluster-variation method. The Hamiltonian is solved within the nine-point-cluster approximation. In contrast to previous studies we find that the phase transition from the superantiferromagnetic to the paramagnetic state is of first order in the range 0.5

publication date

  • 1993-01-01