Tunable insulator-quantum Hall transition in a weakly interacting two-dimensional electron system
1 Graduate Institute of Applied Physics, National Taiwan University, Taipei 106, Taiwan
2 Department of Physics, National Taiwan University, Taipei 106, Taiwan
3 Department of Electronics Engineering, National Chiao Tung University, Hsinchu 300, Taiwan
4 Institute for Solid State Electronics and Center for Micro- and Nanostructures, Technische Universität Wien, Floragasse 7, 1040, Vienna, Austria
5 Department of Electrical Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260-1920, USA
Nanoscale Research Letters 2013, 8:307 doi:10.1186/1556-276X-8-307Published: 3 July 2013
We have performed low-temperature measurements on a gated two-dimensional electron system in which electron–electron (e-e) interactions are insignificant. At low magnetic fields, disorder-driven movement of the crossing of longitudinal and Hall resistivities (ρxx and ρxy) can be observed. Interestingly, by applying different gate voltages, we demonstrate that such a crossing at ρxx ~ ρxy can occur at a magnetic field higher, lower, or equal to the temperature-independent point in ρxx which corresponds to the direct insulator-quantum Hall transition. We explicitly show that ρxx ~ ρxy occurs at the inverse of the classical Drude mobility 1/μD rather than the crossing field corresponding to the insulator-quantum Hall transition. Moreover, we show that the background magnetoresistance can affect the transport properties of our device significantly. Thus, we suggest that great care must be taken when calculating the renormalized mobility caused by e-e interactions.