Critical behavior of an anisotropic Ising antiferromagnet in both external longitudinal and transverse fields

In this paper we study the critical behavior of a two-sublattice Ising model on an anisotropic square lattice in both uniform longitudinal (H  ) and transverse (ΩΩ) fields by using the effective-field theory. The model consists of ferromagnetic interaction Jx in the x direction and antiferromagnetic interaction Jy in the y direction in the presence of the H   and ΩΩ fields. We obtain the phase diagrams in the H–TH–T and Ω–TΩ–T planes changing values of the ΩΩ and H   parameters, respectively for fixed value at λ=Jx/Jy=1λ=Jx/Jy=1. At null temperature, the ground state phase diagram in the Ω–HΩ–H plane for several values of λλ parameter is analyzed. In the particular case of λ=1λ=1 we compare our results with mean-field theory (MFT) and was not observed reentrant behavior around of the critical field Hc/Jy=2.0Hc/Jy=2.0 for Ω=0Ω=0 by using EFT.

► In the last decade there has been a great interest in physics of the quantum phase transition in system at low dimensional. ► In particular, the transverse Ising model has been studied by a variety of approximate methods. ► In the context of quantum phase transition and critical phenomena. ► First time, is presented a study of the superantiferromagnetic transverse Ising model on an anisotropic square lattice. ► We have obtained finite temperature and ground state phase diagrams.