Evidence for a Singlet-Triplet Transition in Spin-Peierls System CuGeO3

Abstract
The magnetic field dependence of the spin-Peierls gap in CuGeO3 has been studied by means of neutron inelastic scattering. The splitting of the single gap state into three distinct excitation branches under a magnetic field can be regarded as direct evidence for the singlet-triplet transition in a spin-Peierls system.