Regensburg 2016 – scientific programme

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DS: Fachverband Dünne Schichten

DS 6: Graphene: Theory
(Joint session of DS, DY, HL, MA, O and TT organized by HL)

DS 6.10: Talk

Monday, March 7, 2016, 12:15–12:30, H17

Interaction-induced conductance from zero modes in a clean magnetic graphene waveguide — •Laura Cohnitz¹, Wolfgang Häusler^2,3, Alex Zazunov¹, and Reinhold Egger¹ — ¹Institut für Theoretische Physik, Heinrich-Heine-Universität, D-40225 Düsseldorf, Germany — ²Institut für Physik, Universität Augsburg, D-86135 Augsburg, Germany — ³Institut für Theoretische Physik, Universität Hamburg, D-20355 Hamburg, Germany

We consider a waveguide formed in a clean graphene monolayer by a spatially inhomogeneous magnetic field. The single-particle dispersion relation for this waveguide exhibits a zero-energy Landau-like at band, while finite-energy bands have dispersion and correspond, in particular, to snake orbits. For zero-mode states, all matrix elements of the current operator vanish, and a finite conductance can only be caused by virtual transitions to finite-energy bands. We show that Coulomb interactions generate such processes. In stark contrast to finite-energy bands, the conductance is not quantized and shows a characteristic dependence on the zero-mode filling. Transport experiments thereby offer a novel and highly sensitive probe of electron-electron interactions in clean graphene samples. We argue that this interaction-driven zero-mode conductor may also appear in other physical settings and is not captured by the conventional Tomonaga-Luttinger liquid description.