spl(2,1) dynamical supersymmetry and suppression of ferromagnetism in flat band double-exchange models
arXiv:cond-mat/0009358 · doi:10.1209/epl/i1999-00520-y
Abstract
The low energy spectrum of the ferromagnetic Kondo lattice model on a N-site complete graph extended with on-site repulsion is obtained from the underlying spl(2,1) algebra properties in the strong coupling limit. The ferromagnetic ground state is realized for 1 and N+1 electrons only. We identify the large density of states to be responsible for the suppression of the ferromagnetic state and argue that a similar situation is encountered in the Kagome, pyrochlore, and other lattices with flat bands in their one-particle density of states.
7 pages, 1 figure