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RESEARCH PRODUCT
Edge-dependent selection rules in magic triangular graphene flakes
H. P. HeiskanenJaakko AkolaM. Manninensubject
Free electron modelPhysicsCondensed Matter - Materials ScienceCondensed matter physicsCondensed Matter - Mesoscale and Nanoscale PhysicsGrapheneFermi levelShell (structure)Materials Science (cond-mat.mtrl-sci)FOS: Physical sciencesFermi energyElectronic structureCondensed Matter PhysicsElectronic Optical and Magnetic Materialslaw.inventionsymbols.namesakeZigzagAtomic orbitallawMesoscale and Nanoscale Physics (cond-mat.mes-hall)symbolsPhysics::Atomic and Molecular Clustersdescription
The electronic shell and supershell structure of triangular graphene quantum dots has been studied using density functional and tight-binding methods. The density functional calculations demonstrate that the electronic structure close to the Fermi energy is correctly described with a simple tight-binding model, where only the ${p}_{z}$ orbitals perpendicular to the graphene layer are included. The results show that (i) both at the bottom and at the top of the ${p}_{z}$ band, a supershell structure similar to that of free electrons confined in a triangular cavity is seen, (ii) close to the Fermi level, the shell structure is that of free massless particles, (iii) triangles with armchair edges show an additional sequence of levels (``ghost states'') absent for triangles with zigzag edges while the latter exhibit edge states, and (iv) the observed shell structure is rather insensitive to the edge roughness.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2008-04-06 |