C. L. Vicente

Electron correlation in the second Landau level: a competition between many nearly degenerate quantum phases.

At a very low-temperature of 9 mK, electrons in the second Landau level of an extremely high-mobility two-dimensional electron system exhibit a very complex electronic behavior. With a varying filling factor, quantum liquids of different origins compete with several insulating phases leading to an irregular pattern in the transport parameters. We observe a fully developed nu=2+2/5 state separated from the even-denominator nu=2+1/2 state by an insulating phase and a nu=2+2/7 and nu=2+1/5 state surrounded by such phases. A developing plateau at nu=2+3/8 points to the existence of other even-denominator states.

Scaling in plateau-to-plateau transition: a direct connection of quantum hall systems with the Anderson localization model.

The quantum Hall-plateau transition was studied at temperatures down to 1 mK in a random alloy disordered high mobility two-dimensional electron gas. A perfect power-law scaling with kappa=0.42 was observed from 1.2 K down to 12 mK. This perfect scaling terminates sharply at a saturation temperature of Ts approximately 10 mK. The saturation is identified as a finite-size effect when the quantum phase coherence length (Lphi proportional, T(-p/2)) reaches the sample size (W) of millimeter scale. From a size dependent study, Ts proportional, W(-1) was observed and p=2 was obtained. The exponent of the localization length, determined directly from the measured kappa and p, is nu=2.38, and the dynamic critical exponent z=1.

Experimental studies of the fractional quantum Hall effect in the first excited Landau level

We present a spectrum of experimental data on the fractional quantum Hall effect (FQHE) states in the first excited Landau level, obtained in an ultrahigh mobility two-dimensional electron system and at very low temperatures, and report the following results. For the even-denominator FQHE states, the sample dependence of the

A-B transition of superfluid {sup 3}He in aerogel and the effect of anisotropic scattering

\ensuremath{\nu}=5∕2

Tilt-induced localization and delocalization in the second Landau level.

state clearly shows that disorder plays an important role in determining the energy gap at

Quantization of the diagonal resistance : Density gradients and the empirical resistance rule in a 2D system

\ensuremath{\nu}=5∕2

Crossover from the nonuniversal scaling regime to the universal scaling regime in quantum Hall plateau transitions

. For the developing

Plateau-to-plateau transitions in random-alloy scattering dominated 2DEGs of different densities

\ensuremath{\nu}=19∕8

Effect of Strong Magnetic Fields on Superfluid 3He in 98% Porosity Aerogel

FQHE state, the temperature dependence of the

The National High Magnetic Field Laboratory Ultra-High B/T Facility

{R}_{xx}