The magnetic behavior of thin ferromagnetic itinerant-electron films is investigated within the strongly correlated single-band Hubbard model. For its approximate solution we apply a generalization of the modified alloy analogy (MAA) to deal with the modifications due to the reduced translational symmetry. The theory is based on exact results in the limit of strong Coulomb interaction which are...

Abstract: We study scattering of a composite quasiparticle, which possesses a degree of freedom corresponding to relative separation between two bound particles, by a delta-like impurity potential on a one-dimensional discrete lattice. Different from a composite object in continuum space, for a composite quasiparticle on a discrete lattice, the entanglement between its relative and centre of ma...

We study a model of quasiparticles on a two-dimensional square lattice coupled to Gaussian distributed dynamical molecular fields. We consider two types of such fields, a vector molecular field that couples to the quasiparticle spin-density and a scalar field coupled to the quasiparticle number density. The model describes quasiparticles coupled to spin or charge fluctuations, and is solved by ...

We study correlation effects and temperature dependencies in the electronic structure of thin ferromagnetic local-moment films. In a first step the Kondo-lattice model is investigated as a candidate for a proper representation of local-moment ferromagnets. Magnetic and electronic key-quantities as the Curie-temperature and the quasiparticle density of states are derived with previously tested m...