PSEUDOSCALAR CHIRAL LONG-RANGE ORDER OF THE S=1/2XY ANTIFERROMAGNET ON THE TRIANGULAR LATTICE

We have studied the pseudoscalar chiral long-range order, based on the local operator chipsi = S1 . (S2 X S3), of the S = 1/2 XY antiferromagnet on the triangular lattice. At finite temperature the chirality has been studied via a seventh-order high temperature series expansion of the square of the fluctuation in the pseudoscalar chiral long-range order. An exact diagonalization study on small finite lattices has been used to investigate the chirality long-range order parameter at T = 0. While Pade approximant analysis of the series suggests the possibility of a finite-temperature phase transition to a low temperature phase with pseudoscalar chiral long-range order, exact diagonalization results indicate that no such order exists at zero temperature.