Fermi surface reconstruction in the Kondo lattice model and the periodic Anderson model

We study the ground state properties of the Kondo lattice model (KLM) and the periodic Anderson model (PAM) in a two-dimensional square lattice with the variational Monte Carlo method. In addition to the conventional second-order antiferromagnetic transition, we find a novel type of quantum phase transition which induces the change of topology of the Fermi surface (Fermi surface reconstruction). The Fermi surface reconstruction is originated from the mechanism of the energy gain and is characteristic both of the KLM and of the PAM. We show the ground state phase diagrams of both models and discuss the relation to the recent experiments which have investigated the change of the Fermi surface.