Arnaud Ralko, Georges Bouzerar
Band ferromagnetism in strongly correlated electron systems is one of the most challenging issue in today's condensed-matter physics. In the quest for the development of nanotechnology and spintronic devices, the ability to control/tune ferromagnetism is one of the keystones. In this spirit and as will be seen, nano-patterned lattices appear to be particularly promising candidates that should, with the tremendous progress in growing and self-organized technics, be synthesized in a near future. Here, we show that the competition between kinetic term and Coulomb repulsion leads to unconventional and complex ferromagnetic phase diagrams: wide region of stability, cascade of transitions, re-entrance, high sensitivity to the carrier concentration. The other major finding is how the so-called Unrestricted Hartree-Fock method is unexpectedly highly accurate (99.9 % match with exact results) and reveals itself to be a fantastic tool to investigate many body physics.
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http://arxiv.org/abs/1206.6218
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