The crystal structure and phonon dynamics of the spin-Peierls material CuGeO3 have been studied by neutron scattering. We found a large lattice anomaly in the a-b plane, perpendicular to the one-dimensional antiferromagnetic spin chain, above the transition temperature. The phonon modes at 100 meV, of the chain oxygens, show anomalous behavior, consistent with structural change. We therefore conclude that the structural evolution of the chain oxygens in the a-b plane, which mediates the spin-spin interaction along the c-axis, drives the spin-Peierls transition.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics