Abstract
Neutron scattering from copper benzoate, , provides the first direct experimental evidence for field-dependent incommensurate low energy modes in a one-dimensional spin antiferromagnet. Soft modes occur for wave vectors , where as predicted by Bethe ansatz and spinon descriptions of the chain. Unexpected was a field-induced energy gap , where as determined from specific heat measurements. At ( ), the magnitude of the gap varies from depending on the orientation of the applied field.
- Received 31 March 1997
DOI:https://doi.org/10.1103/PhysRevLett.79.1750
©1997 American Physical Society