Extinction of the long-range order on site diluted quantum two-dimensional antiferromagnet in Bose–Einstein condensation.

We study the two-dimensional Heisenberg antiferromagnet with ion single anisotropy in the square lattice in the presence of nonmagnetic impurities at T = 0 using the SU(3) Schwinger boson theory. In particular we discuss the influence of site disorder on the quantum phase transition of this model at D c that separates the Néel phase, D < D c , which is gapless, from the disordered phase, gapped phase, D > D c. We find that the long-range order in D < D c for the model without impurities is destroyed for a concentration of nonmagnetic impurities x c ≈ 0. 15. [ABSTRACT FROM AUTHOR]