ADIABATIC APPROXIMATION FOR LOCALIZED-ELECTRONS IN PERIODIC ANDERSON MODEL

The partition function of the periodic Anderson model for an infinite U-term is represented by the path integral over the Grassmann variable s for band s-electrons and supercoherent SU(2\1) variables for localiz ed d-electrons. The effective electron action is obtained for d-electr ons with a level E<0 through the averaging of the thermal distribution over the s-electron trajectories. Due to the spinon-charge separation in the path integral over the d-variables, the low-temperature and sp in mean-field approximations are introduced and are shown to lead to t he adiabatic approximation suggested earlier. Non-linear dependence of the chemical potential mu on the electron concentration Is < 1 is est ablished for the narrow s-electron band w much less than \E\ and the K ondo-like temperature behavior is found for n > 1 in wide w much great er than \E\ s-electron band. (C) 1998 Elsevier Science B.V.