Ferromagnetism in multi–band Hubbard models: From weak to strong Coulomb repulsion

Дата и время публикации : 1996-03-06T17:50:01Z

Авторы публикации и институты :
Karlo Penc
Hiroyuki Shiba
Frédéric Mila
Takuya Tsukagoshi

Ссылка на журнал-издание: Phys. Rev. B 54, 4056 (1996)
Коментарии к cтатье: 12 pages, revtex, 12 figures,needs epsf and multicol style files
Первичная категория: cond-mat

Все категории : cond-mat

Краткий обзор статьи: We propose a new mechanism which can lead to ferromagnetism in Hubbard models containing triangles with different on-site energies. It is based on an effective Hamiltonian that we derive in the strong coupling limit. Considering a one-dimensional realization of the model, we show that in the quarter-filled, insulating case the ground-state is actually ferromagnetic in a very large parameter range going from Tasaki’s flat-band limit to the strong coupling limit of the effective Hamiltonian. This result has been obtained using a variety of analytical and numerical techniques. Finally, the same results are shown to apply away from quarter-filling, in the metallic case.

Category: Physics