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The European Physical Journal B
ISSN: 1434-6028 (printed version)
ISSN: 1434-6036 (electronic version)
Abstract Volume 2 Issue 1 (1998) pp 11-16
Ferromagnetic ground state in the Kondo lattice model
S.-Q. Shen (a)
Department of Physics, The University of Hong Kong, Pokfulam Road, Hong Kong
Received: 10 September 1997 / Revised: 15 October 1997 / Accepted: 17 October 1997
Abstract: We present a series of rigorous examples of the Kondo lattice model that exhibit full ferromagnetism in the ground state. The models are defined in one-, two- and three-dimensional lattices, and are characterized by a range of hopping terms, specific electron filling, and large ferromagnetic coupling. Our examples show that a sufficient strong but finite exchange coupling between conduction electrons and localized spins could overcome the competition from mobility of a finite density of electrons and drive the system from a paramagnetic phase to a ferromagnetic phase. We also establish a relation of ferromagnetism between the Hubbard model and Kondo lattice model. Meanwhile some rigorous results on ferromagnetism in the corresponding Hubbard model are presented.
PACS. 75.10.Lp Band and itinerant models - 75.50.-y Studies of specific magnetic materials
(a) email: sshen@kkucc.hku.hk
Online publication: April 21, 1998
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