Dirac fermion heating, current scaling, and direct insulator-quantum Hall transition in multilayer epitaxial graphene
1 Graduate Institute of Applied Physics, National Taiwan University, Taipei 106, Taiwan
2 Department of Physics, National Taiwan University, Taipei 106, Taiwan
3 National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568, Japan
4 National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899, USA
Nanoscale Research Letters 2013, 8:360 doi:10.1186/1556-276X-8-360Published: 22 August 2013
We have performed magnetotransport measurements on multilayer epitaxial graphene. By increasing the driving current I through our graphene devices while keeping the bath temperature fixed, we are able to study Dirac fermion heating and current scaling in such devices. Using zero-field resistivity as a self thermometer, we are able to determine the effective Dirac fermion temperature (TDF) at various driving currents. At zero field, it is found that TDF ∝ I≈1/2. Such results are consistent with electron heating in conventional two-dimensional systems in the plateau-plateau transition regime. With increasing magnetic field B, we observe an I-independent point in the measured longitudinal resistivity ρxx which is equivalent to the direct insulator-quantum Hall (I-QH) transition characterized by a temperature-independent point in ρxx. Together with recent experimental evidence for direct I-QH transition, our new data suggest that such a transition is a universal effect in graphene, albeit further studies are required to obtain a thorough understanding of such an effect.