Spin-wave results for the triangular Heisenberg antiferromagnet

Abstract

We perform the standard spin-wave analysis of the triangluar Heisenberg quantum antiferromagnet. Contrary to the variational calculation of Anderson, we diagonalize exactly the quadratic part of the spin-wave Hamiltonian and obtain results in a 1/S expansion. We compute the ground-state staggered magnetization per spin and the ground-state energy. For spin (1/2, the agreement with the variational values of Huse and Elser suggests that the trangular lattice has long-range magnetic order.