COLLECTIVE KONDO EFFECT IN THE ANDERSON-HUBBARD LATTICE

The periodic Anderson model is extended by switching on a Hubbard U fo r the conduction electrons. We use the Gutzwiller variational method t o study the nearly integral valent limit. The lattice Kondo energy con tains the U-dependent chemical potential of the Hubbard subsystem in t he exponent, and the correlation-induced band narrowing in the prefact or. Both effects tend to suppress the Kondo scale, which can be unders tood to result from the blocking of hybridization. At half-filling, we find a Brinkman-Rice-type transition from a Kondo insulator to a Mott insulator.