Abstract
The magnetic excitations of the square-lattice spin-1/2 antiferromagnet and high- parent compound are determined using high-resolution inelastic neutron scattering. Sharp spin waves with absolute intensities in agreement with theory including quantum corrections are found throughout the Brillouin zone. The observed dispersion relation shows evidence for substantial interactions beyond the nearest-neighbor Heisenberg term which can be understood in terms of a cyclic or ring exchange due to the strong hybridization path around the square plaquettes.
- Received 21 June 2000
DOI:https://doi.org/10.1103/PhysRevLett.86.5377
©2001 American Physical Society