Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

HL: Fachverband Halbleiterphysik

HL 22: Graphene 2 (Joint Session with TT)

HL 22.5: Vortrag

Dienstag, 23. März 2010, 10:30–10:45, H21

Electronic properties of graphene nanoribbons under gate electric fields — •Tobias Burnus¹, Daniel Wortmann¹, Yuriy Mokrousov¹, Gustav Bihlmayer¹, Stefan Blügel¹, and Klaus Michael Indlekofer² — ¹Institut für Festkörperforschung & Institute for Advanced Simulation, Forschungszentrum Jülich, 52425 Jülich, Germany — ²Hochschule RheinMain, Unter den Eichen 5, 65195 Wiesbaden, Germany

Graphene nanoribbons (GNR) hold great future promise for field-effect transistor and quantum dot (QD) devices. The gate electrodes and the electric field distribution play a crucial role. For a realistic description of a quantum dot, the many-body interaction of the few electrons in the quantum dot have to be described properly. The QD itself is formed by the vast number of electrons in a many nanometer long ribbon under the presence of a gate. As a first step, the GNR is calculated using density-functional theory (DFT), where the gate electrode is simulated by an inhomogeneous charge-sheet placed atop of the ribbon. Hereby, all electrons in the GNR are taken into account and one can directly calculate the dielectric constant ε and changes in the charge density due to the applied voltage on the gates. Using this technique, adatoms or different ribbon terminations can be taken into account. Based on the resulting matrix elements, the few electron problem of the GNR QD is treated within a relevant many-body subspace by means of configuration interaction (CI). In the presentation, the first result along this line will be shown. The work is supported by the DFG Research Unit 912 “Coherence and Relaxation Properties of Electron Spins”.