Ground state and low-lying excitations of the spin-1/2 XXZ model on the kagome lattice at magnetization 1/3

A. HONECKER, D.C. CABRA, M.D. GRYNBERG, P.C.W. HOLDSWORTH, P. PUJOL, J. RICHTER, D. SCHMALFUSS, J. SCHULENBURG

PHYSICA B - CONDENSED MATTER

ELSEVIER SCIENCE BV

Año: 2005 vol. 359 p. 1391 - 1393

0921-4526

We study the ground state and low-lying excitations of the S=1/2 XXZ antiferromagnet on the kagome lattice at magnetization one third of the saturation. An exponential number of non-magnetic states is found below a magnetic gap. The non-magnetic excitations also have a gap above the ground state, but it is much smaller than the magnetic gap. This ground state corresponds to an ordered pattern with resonances in one third of the hexagons. The spin-spin correlation function is short ranged, but there is long-range order of valence-bond crystal type.