Influence of Band and Orbital Degeneracies on Ferromagnetism in the Periodic Anderson Model

Abstract

We investigate the influence of degeneracies of the conduction band and the $f$-orbital on the stability of ferromagnetism in the periodic Anderson model. To this end we calculate the temperature dependence of the inverse susceptibility for different degeneracies $D^c,D^f$ and conduction electron densities $n^c$ within the dynamical mean-field theory. A strong increase of the Curie temperature $T_c$ with the degeneracy $D^f$ of the localized $f$-level is found. For $D^c\le D^f$ a simple \emph{ansatz} based on a mean-field treatment of the RKKY interaction is shown to imply a scaling behavior of $T_c$ as a function of the conduction electron density per band which is well obeyed by the numerical results. In particular, $T_c$ is found to have a maximum at $n^c/D^c\approx 0.3$.

5 pages, 4 figures (accepted for publication in Phys. Rev. B)

References in corpus (3)

• CeRuPO: A rare example of a Ferromagnetic Kondo lattice
• Quantum Monte Carlo study for multiorbital systems with preserved spin and orbital rotational symmetries
• Ferromagnetism and Kondo Insulator Behavior in the Disordered Periodic Anderson Model