One-dimensional antiferromagnetic coupling in the low-carrier heavy-electron system Yb4As3: The role of charge ordering

Inelastic-neutron-scattering experiments on Yb4As3 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 Yb4As3 is a unique phenomenon caused by charge ordering: it results from the fact that the compound contains doped one-dimensional 4f(1) hole chains with strong on-site f-electron correlations. [S0163-1829(97)50642-4].