Berlin 2015 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 34: Transport: Graphene (jointly with CPP, DS, DY, HL, MA, O)

TT 34.9: Talk

Tuesday, March 17, 2015, 11:45–12:00, A 053

Transport phenomena in deformed graphene: Magnetic field versus curvature — Thomas Stegmann^1,2 and •Nikodem Szpak¹ — ¹Fakultät für Physik, Universität Duisburg-Essen, Duisburg, Germany — ²Instituto de Ciencias Fisicas, Universidad Nacional Autonoma de Mexico, Cuernavaca, Mexico

The current flow in deformed graphene nanoribbons is studied theoretically. Using a tight-binding model, we apply the nonequilibrium Green's function (NEGF) method to investigate how a localized deformation and a perpendicular magnetic field affect the current flow. At long wavelengths, the eikonal approximation applied to the effective Dirac equation leads to the Mathisson-Papapetrou equations describing trajectories of a spinning point-like particle in a curved space. We show that these trajectories are compatible with the current flow paths of the NEGF calculations. The deformation has two-fold effect on them: First, via a pseudo-magnetic field, with sixfold symmetry of attractive and repulsive regions, which acts differently on electrons and holes, but changes its sign when going from the K to the K' point. Second, via an attractive force due to the curvature of the ribbon, which treats electrons and holes equivalently. We conclude with an outlook on how to use deformed graphene ribbons for geometrical focusing of the current flow.