Neutron and x-ray scattering studies of the lightly doped spin–Peierls systemCu1−xCdxGeO3

Abstract

Single crystals of the lightly doped spin–Peierls systemCu1−xCdxGeO3 have been studied using bulk susceptibility, x-ray diffraction, and inelasticneutron scattering techniques. We investigate the triplet gap in the magneticexcitation spectrum of this quasi-one-dimensional quantum antiferromagnet, andits relation to the spin–Peierls dimerization order parameter. We employ twodifferent theoretical forms to model the inelastic neutron scattering cross section andχ′′(Q,ω), and show the sensitivity of the gap energy to the choice of ). We find that a finite gap exists at the spin–Peierls phase transition.