Nianpei Deng

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We report quantitative measurements of the impact of alloy disorder on the ν = 5/2 fractional quantum Hall state. Alloy disorder is controlled by the aluminum content x in the Al(x)Ga(1-x)As channel of a quantum well. We find that the ν = 5/2 state is suppressed with alloy scattering. To our surprise, in samples with alloy disorder the ν = 5/2 state appears(More)
We study Escherichia coli chemotaxis behavior in environments with spatially and temporally varying attractant sources by developing a unique microfluidic system. Our measurements reveal a frequency-dependent chemotaxis behavior. At low frequency, the E. coli population oscillates in synchrony with the attractant. In contrast, in fast-changing environments,(More)
We report an unexpected sharp peak in the temperature dependence of the magnetoresistance of the reentrant integer quantum Hall states in the second Landau level. This peak defines the onset temperature of these states. We find that in different spin branches the onset temperatures of the reentrant states scale with the Coulomb energy. This scaling provides(More)
Nianpei Deng,1 J. D. Watson,1 L. P. Rokhinson,1,2 M. J. Manfra,1,2,3 and G. A. Csáthy1,2,* 1Department of Physics, Purdue University, West Lafayette, Indiana 47907, USA 2Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA 3School of Materials Engineering and School of Electrical and Computer Engineering, Purdue University,(More)
We report drastically different onset temperatures of the reentrant integer quantum Hall states in the second and third Landau levels. This finding is in quantitative disagreement with the HartreeFock theory of the bubble phases which is thought to describe these reentrant states. Our results indicate that the association of the reentrant states in the(More)
Deng, Nianpei. Ph.D., Purdue University, December 2014. Transport Studies of Reentrant Integer Quantum Hall States Forming in The Two-dimensional Electron Gas. Major Professor: Gábor A. Csáthy. The two dimensional electron gas subjected to a magnetic field has been a model system in contemporary condensed matter physics which generated many beautiful(More)
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