Quantum critical point in a periodic Anderson model - art. no. 195123

We investigate the symmetric periodic Anderson model (PAM) on a three-dimen sional cubic lattice with nearest-neighbor hopping and hybridization matrix elements. Using Gutzwiller's variational method and the Hubbard-III approx imation (which corresponds to an exact solution of the appropriate Falicov- Kimball model in infinite dimensions) we demonstrate the existence of a qua ntum critical point at zero temperature. Below a critical value V-c of the hybridization (or above a critical interaction U-c) the system is an insula tor in Gutzwiller's and a semimetal in Hubbard's approach, whereas above V- c (below U-c) it behaves like a metal in both approximations. These predict ions are compared with the density of states of the d and f bands calculate d from quantum Monte Carlo and numerical renormalization group calculations . Our conclusion is that the half-filled symmetric PAM contains a metal-sem imetal transition, not a metal-insulator transition as has been suggested p reviously.