Possibility of a sublattice order of the kagomé antiferromagnet

The properties of the ground state and the low-lying states of the antiferromagnetic Heisenberg model on the kagomé lattice are discussed by an effective linear-spin-wave scheme. A novel scheme is introduced in the present paper. By using this scheme, the staggered magnetization of one of the sublattices and the ground-state energy are evaluated, and a finite positive value of the staggered magnetization is obtained. Then a physical picture of the ground state and the low-lying states is suggested.