A SCHWINGER BOSON APPROACH TO HEISENBERG ANTIFERROMAGNETS ON A TRIANGULAR LATTICE

The ground-state properties of generalized S = 1/2 Heisenberg antiferromagnets on a triangular lattice are studied by means of the Schwinger boson approach. The generalizations considered include second-neighbour interactions and nearest-neighbour couplings breaking the rotational symmetry of the lattice. Unlike in previous work using the same representation of spin operators, good quantitative agreement with exact numerical results and with other approximate methods is obtained. The results point to the existence of magnetic long-range order, with a local magnetization M = 0.275 for the standard nearest-neighbour model.