Quantum Hall Effect in Two-Terminal Graphene Devices.

We report on transport measurements in the quantum Hall regime of two-terminal single and bilayer graphene devices. The mixture of the longitudinal and transverse conductivities in the two-terminal geometry results in departures from the expected conductance values on the Hall plateaus and are found to be device-geometry dependent. The experimental results are compared to theory and discrepancies are discussed. Research supported in part by INDEX, an NRI Center, and by the Harvard NSEC.