Quantum phase transition in the two dimensional XY model with single ion and exchange anisotropies

• The SU(3) Schwinger boson formalism is used in this paper.
• The phase diagram at zero temperature is obtained.
• The energy gap as a function of the anisotropy parameter and temperature is calculated.

I study the spin-one XY antiferromagnet with easy plane single ion and exchange anisotropies on the square lattice using the SU(3) Schwinger boson formalism. The phase diagram at zero temperature is obtained. The gap, in the disordered phase, as a function of temperature is presented.