Magnetic exchange mechanism for electronic gap opening in graphene

¹ Instituto de Física, Universidade Federal do Rio de Janeiro - CP 68.528, 21941-972 Rio de Janeiro RJ, Brazil
² Instituto de Física, Universidade Federal de Mato Grosso - 78060-900, Cuiabá MT, Brazil
³ Department of Physics, University of Illinois at Urbana-Champaign - 1110 W. Green St, Urbana, IL 61801, USA
⁴ Graphene Research Centre, National University of Singapore - 2 Science Drive 3, Singapore 117542

^a tgrappoport@pq.cnpq.br

Received: 8 May 2011
Accepted: 31 August 2011

Abstract

We show within a local self-consistent mean-field treatment that a random distribution of magnetic adatoms can open a robust gap in the electronic spectrum of graphene. The electronic gap results from the localization of the charge carriers that arises from the interplay between the graphene sublattice structure and the exchange interaction between the adatoms. The size of the gap depends on the strength of the exchange interaction between carriers and localized spins and can be controlled by both temperature and external magnetic field. Furthermore, we show that an external magnetic field creates an imbalance of spin-up and spin-down carriers at the Fermi level, making doped graphene suitable for spin injection and other spintronic applications.