1301.2117 (Denis Golez et al.)

Fermi-pocket-vanishing phase transition in the ferromagnetic phase of
the Kondo lattice model    [PDF]

Denis Golez, Rok Zitko

By performing extensive dynamical mean-field theory calculations with the numerical renormalization group as the impurity solver, we establish the low-temperature phase diagrams of the spin-1/2 and spin-1 Kondo lattice models as a function of the conduction-band filling and the exchange coupling strength in the regime of ferromagnetic RKKY interactions (i.e., for low and moderate electron density). We show that both models have two distinct ferromagnetic phases separated by a continuous Lifshitz transition of the Fermi pocket vanishing type: one phase has a true gap in the minority band, the other only a pseudogap. The two phases can be experimentally distinguished by their magnetization curves; only the first phase exhibits magnetization rigidity. We find that, quite generically, ferromagnetism and Kondo screening coexist rather than compete, both in spin-1/2 and spin-1 models. We compute the Curie temperatures and establish a "ferromagnetic Doniach diagram" for both models.

View original: http://arxiv.org/abs/1301.2117