AC quantum Hall effect in epitaxial graphene

摘要

This paper describes measurements of the AC quantum Hall resistance in epitaxial graphene performed with a newly developed digitally assisted impedance bridge. Capacitive losses cause a negative frequency dependence of the quantum Hall resistance, in contrast to the positive frequency dependence observed in GaAs devices. The magnitude of the frequency dependence varies among individual graphene samples and can be significantly larger than in GaAs devices.