The Slave-Boson Mean Field Theory of a Modified Periodic Anderson Model

The coherent band states of the infinite U lattice Anderson model with introducing a small dispersion into the f-band are derived in the framework of the slave-boson mean field theory. The temperature dependences of the pseudogap in f-band conduction electrons' density of states near the Fermi level are calculated self-consistently. The calculation is applied to discuss the low temperature properties of the heavyelectron metals. The results show that with decreasing temperature the coefficient of the thermoelectric power Q changes sign below the Kondo temperature T_k, and an additional positive peak will appear at the rather lower temperatures, which are in agreement with the experimental results in CeAl₃.