Bilayer graphene: gap tunability and edge properties

• Type: Article in International Conference Proceedings Book
• Date: 2008

Authors

Eduardo V Castro (Author) FCUP; Peres, NMR (Author) Other; Lopes dos Santos, JMBL (Author) FCUP; Guinea, F (Author) Other; Castro Neto, AH (Author) Other

Conference proceedings International

Title: INTERNATIONAL CONFERENCE ON THEORETICAL PHYSICS 'DUBNA-NANO2008'

Final page: 012002

International Conference on Theoretical Physics (Dubna-Nano2008)

Dubna, RUSSIA, JUL 07-11, 2008

Indexing

ISI Web of Knowledge - 42 Citations

Scopus - 43 Citations

Scientific classification

FOS: Engineering and technology > Nano-technology

Other information

Authenticus ID: P-004-3MD

DOI: 10.1088/1742-6596/129/1/012002

Abstract (EN): Bilayer graphene - two coupled single graphene layers stacked as in graphite - provides the only known semiconductor with a gap that can be tuned externally through electric field effect. Here we use a tight binding approach to study how the gap changes with the applied electric field. Within a parallel plate capacitor model and taking into account screening of the external field, we describe real back gated and/or chemically doped bilayer devices. We show that a gap between zero and midinfrared energies can be induced and externally tuned in these devices, making bilayer graphene very appealing from the point of view of applications. However, applications to nanotechnology require careful treatment of the efiect of sample boundaries. This being particularly true in graphene, where the presence of edge states at zero energy - the Fermi level of the undoped system - has been extensively reported. Here we show that also bilayer graphene supports surface states localized at zigzag edges. The presence of two layers, however, allows for a new type of edge state which shows an enhanced penetration into the bulk and gives rise to band crossing phenomenon inside the gap of the biased bilayer system.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8