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Accueil du site > Vie du Laboratoire > Archives > Archives 2015 "A la Une" >

9 octobre 2015

Ferromagnetism and Phase Separation of Strongly Correlated Electrons

In this work we focus on the extended nondegenerate Hubbard model which describes the simplest correlated metals and investigate the influence of intersite Coulomb and exchange interactions on the charge and magnetic instabilities. We present numerical analysis for a representative example of a three-dimensional cubic lattice. To that aim we adopt and extend the spin-rotation-invariant Kotliar and Ruckenstein slave boson representation.

Instability lines of the unpolarized state towards ferromagnetic order as given by the divergence of the magnetic susceptibility for the Hubbard model extended by a ferromagnetic exchange J<0 on the cubic lattice. Different lines from top to bottom for : J/U=0, -0.01, -0.05, -0.1, -0.15, -0.2.

Landau parameters Fs0 for the Hubbard model on the cubic lattice extended by attractive density-density interactions V/U = -0.2. Ferromagnetic and charge instabilities are found in large regions of the phase diagram.

By : G. Lhoutellier, R. Frésard et A. M. Oles,
Phys. Rev. B 91, 224410 (2015)

Nouveaux Matériaux : Fondements, Fonctionnalités (NMF2)