Itinerant-localized duality model for heavy fermions and strongly correlated metals

A concept of duality of itenerant and localized characters of electrons in strongly correlated metals, such as heavy fermions and high-T_c cuprates, is shown to be useful to understand the anomalous properties in their normal and ordered states. The systematics of metamagnetic behavior in the paramagnetic phase and a possible origin of the weak antiferromagnetism of heavy fermions are explained on the basis of the duality model, a semi-phenomenology which takes explicitly into account such dual nature of electrons. The duality model also gives us a basis for understanding some of the anomalous behaviors of high-T_c cuprates in their normal state in a constant way.