title: Biased bilayer graphene: semiconductor with a gap tunable by the electric field effect.
abstract: We demonstrate that the electronic gap of a graphene bilayer can be controlled externally by applying a gate bias. From the magnetotransport data (Shubnikov-de Haas measurements of the cyclotron mass), and using a tight-binding model, we extract the value of the gap as a function of the electronic density. We show that the gap can be changed from zero to midinfrared energies by using fields of less, approximately < 1 V/nm, below the electric breakdown of SiO2. The opening of a gap is clearly seen in the quantum Hall regime.
authors.affiliation: CFP and Departamento de Física, Faculdade de Ciências Universidade do Porto, P-4169-007 Porto, Portugal.
authors.forename: Eduardo V
authors.initials: EV
authors.lastname: Castro
authors.forename: K S
authors.initials: KS
authors.lastname: Novoselov
authors.forename: S V
authors.initials: SV
authors.lastname: Morozov
authors.forename: N M R
authors.initials: NM
authors.lastname: Peres
authors.forename: J M B Lopes
authors.initials: JM
authors.lastname: dos Santos
authors.forename: Johan
authors.initials: J
authors.lastname: Nilsson
authors.forename: F
authors.initials: F
authors.lastname: Guinea
authors.forename: A K
authors.initials: AK
authors.lastname: Geim
authors.forename: A H Castro
authors.initials: AH
authors.lastname: Neto