Place: Room 321, main building of Institute of Solid State Physics
Time: 3:00p.m., Friday, May 14, 2010
Abstract:
We review the transmission through single-layer graphene nanostructures as a function of the incident wave vector or other parameters such as barrier widths, well depths, magnetic field, etc.. In these graphene structures the carriers behave nearly as massless,“relativistic” fermions with the "light speed" replaced by the Fermi velocity. Several particular cases are considered: single and double barriers,wells, as well as magnetic barriers. The latter can be realized by placing nanostructured ferromagnetic stripes on top of a grapheme layer. Resonant features in the transmission through double barriers result from resonant electron states in the wells or hole states in the barriers and strongly influence the ballistic conductance of the structures. In all cases the transmission depends strongly on the direction of the incident electron or hole wave vector and gives the possibility to construct direction-dependent, wave vector filters. In general, the resonant structure of the transmission is significantly more pronounced for (Dirac) electrons with linear spectrum than for the usual electrons with a parabolic spectrum. Similar results are obtained for bilayer graphene nanostructures. In addition, we study in detail Fabry-Pérot oscillations in the transmission and conductance and their dependence on magnetic field and shape of the barriers.
