Eur. Phys. J. B 75, 511-525 (2010)
https://doi.org/10.1140/epjb/e2010-00160-0

Ferromagnetism without flat bands in thin armchair nanoribbons

Department of Theoretical Physics, University of Debrecen, 4010 Debrecen, Hungary

Corresponding author: ^a gulacsi@phys.unideb.hu

Received: 7 January 2010
Revised: 30 March 2010
Published online: 26 May 2010

Abstract

Describing by a Hubbard type of model a thin armchair graphene ribbon in the armchair hexagon chain limit, one shows in exact terms, that even if the system does not have flat bands at all, at low concentration a mesoscopic sample can have ferromagnetic ground state, being metallic in the same time. The mechanism is connected to a common effect of correlations and confinement.