Szczegóły publikacji
Opis bibliograficzny
Charging graphene nanoribbon quantum dots / D. P. ŻEBROWSKI, B. SZAFRAN // Physical Review. B, Condensed Matter and Materials Physics ; ISSN 1098-0121. — Tytuł poprz.: Physical Review B : Condensed Matter. — 2015 — vol. 92 iss. 8, s. 085307-1–085307-11. — Bibliogr. s. 085307-11
Autorzy (2)
Dane bibliometryczne
| ID BaDAP | 92055 |
|---|---|
| Data dodania do BaDAP | 2015-10-05 |
| Tekst źródłowy | URL |
| DOI | 10.1103/PhysRevB.92.085307 |
| Rok publikacji | 2015 |
| Typ publikacji | artykuł w czasopiśmie |
| Otwarty dostęp |  |
| Czasopismo/seria | Physical Review, B |
Abstract
We describe charging a quantum dot induced electrostatically within a semiconducting graphene nanoribbon by electrons or holes. The applied model is based on a tight-binding approach with the electron-electron interaction introduced by a mean-field local-spin-density approximation. The numerical approach accounts for the charge of all the p(z) electrons and screening of external potentials by states near the charge-neutrality point. Both a homogeneous ribbon and a graphene flake embedded within the ribbon are discussed. The formation of transport gaps as functions of the external confinement potential (top-gate potential) and the Fermi energy (back-gate potential) are described in a qualitative agreement with the experimental data. For a fixed number of excess electrons, we find that the excess charge added to the system is, - depending on the voltages defining the work point of the device, (i) delocalized outside the quantum dot, - in the transport gap due to the top-gate potential; (ii) localized inside the quantum dot, - in the transport gap due to the back-gate potential; or (iii) extended over both the quantum dot area and the ribbon connections, - outside the transport gaps. The applicability of the frozen valence-band approximation to describe charging the quantum dot by excess electrons is also discussed.
