[Zurück]

F. Libisch:
"The Electronic Structure of Graphene Nanostructures";
Vortrag: Seminar Talk, University of Napels Federico II, Naples, Italy (eingeladen); 20.03.2015.

The special properties of graphene have created wide interest in possible graphene-based nanoelectronic devices. A theoretical understanding of the electronic structure of graphene in different chemical environments, and ways to tailor them, are crucial for future device applications. We investigate the electronic structure of nanostructured graphene at different length scales, and different levels of theory. For periacene atoms, small building blocks for graphene nanodevices, high-level correlated wavefunction methods (AQCC) reveal a high degree of radicality, as evident by fractional occupations of many orbitals. For small graphene flakes (of the order of a few nanometers) grown on iridium (111), we compare STM
measurements with DFT and tight-binding calculations and find good agreement: at the flake edges, partially covalent bonding with the metal surface leads to strong hybridization between the graphene bands and the iridium surface state. Even larger quantum dot devices (of the order of 50 nm in diameter) can be treated by tight-binding approaches: we find that the edge roughness induced by the lithographic pattering of the dots dominates their properties.