Low Temperature Behavior of Itinerant Ferromagnet Realized in Extended Nagaoka Mechanism

This is the authors' abstract. We don't add key points for this paper.

We have proposed a Hubbard model which exhibits itinerant ferromagnetism by extending the model of Nagaoka ferromagnetism.In contrast to the original Nagaoka model, our model shows a ferromagnetic state at finite electron density in the thermodynamic limit.To control the electron density, we introduce a system with a lattice which consists of a part of system and a part of particle bath.The electron distribution is controlled by the difference of the chemical potentials of both parts.We show that this idea of the realization of itinerant ferromagnetism works in two-and three-dimensional lattices as well as a one-dimensional lattice which we studied previously.We also investigate the temperature dependence of the magnetic ordering and present a magnetic phase diagram in the space of the temperature and the chemical potential.