New critical behaviour of the three-dimensional Ising model with nearest-neighbor, next-nearest-neighbor and plaquette interactions

Cirillo, E. N. M.; Gonnella, G.; Pelizzola, A.

New critical behaviour of the three-dimensional Ising model with nearest-neighbor, next-nearest-neighbor and plaquette interactions

Authors

Cirillo, E. N. M.

Gonnella, G.

Pelizzola, A.

Description

The critical and multicritical behavior of the simple cubic Ising model with nearest-neighbor, next-nearest-neighbor and plaquette interactions is studied using the cube and star-cube approximations of the cluster variation method and the recently proposed cluster variation--Padé approximant method. Particular attention is paid to the line of critical end points of the ferromagnetic-paramagnetic phase transition: its (multi)critical exponents are calculated, and their values suggest that the transition belongs to a novel universality class. A rough estimate of the crossover exponent is also given.
7 pages REVTeX + 2 PostScript figures, to be published in Phys. Rev. E as a Rapid Communication