Ferroquadrupolar phase of the S=1 bilinear–biquadratic Heisenberg model on the square lattice

Using the SU(3) Schwinger bosons formalism in a mean field approximation we have investigated the ferroquadrupolar phase of the S=1 Heisenberg model with bilinear and biquadratic exchange interactions on the square lattice. This nonmagnetic phase is characterized by a finite quadrupole moment. We have compared our results with the ones obtained from other theories. - Highlights: • The quadrupole moment of the ferroquadrupolar phase is calculated. • The static spin structure factor is obtained. • The quadrupole structure factor is calculated and shows to diverge at q=(0,0)