GROUND-STATE SELECTION IN A KAGOME ANTIFERROMAGNET

We address selection of a spin-ordered ground state in the quantum Hei senberg nearest-neighbor antiferromagnet with large spin S on the high ly frustrated Kagome lattice. By treating the anharmonic terms in the spin-wave expansion, we obtain an effective Hamiltonian bilinear in Is ing variables which parametrize the infinity of coplanar classical gro und states. This favors 'root 3 X root 3'spin order, in accordance wit h prior expectations.