High-Field Electronic Properties of Graphene

作者：Zeitler U^*; Gie**ers A J M; McCollam A; Kurganova E V; van Elferen H J; Maan J C

来源：Journal of Low Temperature Physics, 2010, 159(1-2): 238-244.

DOI：10.1007/s10909-009-0100-z

• Graphene
• Quantum Hall effect
• Landau levels

We have measured the energy gaps in single-layer and bilayer graphene by means of temperature dependent transport experiments in high magnetic fields up to 33 T. They follow the expected Landau level splitting when a finite level width is taken into account. The quantum Hall effect, hitherto only observed up to 30 K, remains visible up to 200 K in bilayers and even up to room temperature in single-layer graphene. Our experiments in single-layer graphene show that the lowest Landau level, shared equally between electrons and holes at zero energy, becomes extremely narrow in high magnetic fields. It is this narrowing, together with the large Landau level splitting in graphene that leads to an extremely robust localization and makes the quantum Hall effect visible up to room temperature. In high magnetic fields (B > 20 T) we observe a strongly increasing resistance with decreasing temperature. These results are explained with field dependent splitting of the lowest Landau level of the order of a few Kelvin, as extracted from activated transport measurements.

• 出版日期2010-4