Dresden 2017 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 66: Focus Session on 2D Materials: Ballistic Quantum Transport in Graphene (jointly with DY, DS, HL, MA, O)

HL 66.5: Hauptvortrag

Donnerstag, 23. März 2017, 11:45–12:15, HSZ 03

Interaction-Induced Conductance from Zero Modes in a Magnetic Graphene Waveguide — Alex Zazunov¹ and •Wolfgang Häusler² — ¹Heinrich-Heine-Universität Düsseldorf — ²Uni Augsburg

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 flat 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.