SU(2) Schwinger boson theory of the frustrated two-dimensional antiferromagnet

We have obtained the temperature T0 of a phase transition in this model as a function of the frustration parameter J2 in the S=1/2 two-dimensional frustrated Heisenberg antiferromagnet in the square lattice considering second-neighbor interactions in the diagonal. We have employed the SU(2) Schwinger boson formalism to obtain the behavior of T0 vs. J2. We have considered the inter-chain coupling in the diagonal as antiferromagnetic, J2>0, and the nearest-neighbor coupling as antiferromagnetic J1>0. The critical temperature T0 is the temperature where the correlation length ξ(T0)→0.