One-dimensional antiferromagnetic coupling in the low-carrier heavy-electron system The role of charge ordering

Inelastic-neutron-scattering experiments on (Formula presented) revealed the existence of low-energy spin excitations, which are characteristic of a one-dimensional Heisenberg-type antiferromagnetic coupling at low temperatures where charge ordering takes place. Superimposed on the one-dimensional spin excitations, an unusual magnetic response is also observed around the one-dimensional zone center. These results strongly suggest that the heavy-electron behavior in (Formula presented) is a unique phenomenon caused by charge ordering; it results from the fact that the compound contains doped one-dimensional (Formula presented) hole chains with strong on-site (Formula presented)-electron correlations.