Related papers: Spin Polarization of the 12/5 Fractional Quantum H…
Using a 50-nm width, ultra-clean GaAs/AlGaAs quantum well, we have studied the Landau level filling factor $\nu = 5/2$ fractional quantum Hall effect in a perpendicular magnetic field $B \sim$ 1.7 T and determined its dependence on tilted…
Magnetotransport measurements on two-dimensional electrons confined to wide GaAs quantum wells reveal a remarkable evolution of the ground state at filling factor $\nu=1/2$ as we tilt the sample in the magnetic field. Starting with a…
Using a tilted field geometry, the effect of an in-plane magnetic field on the even denominator nu = 5/2 fractional quantum Hall state is studied. The energy gap of the nu = 5/2 state is found to collapse linearly with the in-plane magnetic…
We study the \nu=5/2 even-denominator fractional quantum Hall effect (FQHE) over a wide range of magnetic (B) field in a heterojunction insulated gate field-effect transistor (HIGFET). The electron density can be tuned from n=0 to 7.6…
The activation gap Delta of the fractional quantum Hall state at constant filling n =1/3 is measured in wide range of perpendicular magnetic field B. Despite the full spin polarization of the incompressible ground state, we observe a sharp…
We report on the dramatic evolution of the quantum Hall ferromagnet in the fractional quantum Hall regime at $\nu = 2/5$ filling. A large enhancement in the characteristic timescale gives rise to a dynamical transition into a novel…
The fractional quantum Hall (FQH) effect at filling factor v = 5/2 has recently come under close scrutiny, as it may possess quasi-particle excitations obeying nonabelian statistics, a property sought for topologically protected quantum…
The fractional quantum Hall effect (FQHE) of topological surface-state particles under a tilted strong magnetic field is theoretically studied by using the exact diagonalization method. The Haldane's pseudopotentials for the Coulomb…
We numerically study the fractional quantum Hall effect at filling factors $\nu=12/5$ and 13/5 (the particle-hole conjugate of 12/5) in high-quality two-dimensional GaAs heterostructures via exact diagonalization including finite well width…
We report the observation of a fully developed fractional quantum Hall state at $\nu=5/2$ in GaAs/Al$_{x}$Ga$_{1-x}$As quantum wells with mobility well below $10^{7}$\thinspace cm$^{2}$/Vs. This is achieved either by strong illumination or…
We report magneto-transport measurements for the fractional quantum Hall state at filling factor $\nu=$ 5/2 as a function of applied parallel magnetic field ($B_{||}$). As $B_{||}$ is increased, the 5/2 state becomes increasingly…
We present here the results from a density dependent study of the activation energy gaps of the fractional quantum Hall effect states at Landau level fillings \nu=8/3 and 7/3 in a series of high quality quantum wells. In the density range…
We present a study of the angular dependence of the resistivity tensor up to 35 T in elemental bismuth complemented by torque magnetometry measurements in a similar configuration. For at least two particular field orientations a few degrees…
We studied neutral excitations in a two-dimensional electron system with an orbital momentum $\Delta M = 1$ and spin projection over magnetic field axis $\Delta S_z = 1$ in the vicinity of a filling factor of 3/2. It is shown that the 3/2…
We report magneto-transport measurements in wide GaAs quantum wells with tunable density to probe the stability of the fractional quantum Hall effect at filling factor $\nu = $ 5/2 in the vicinity of the crossing between Landau levels (LLs)…
We have observed in a low density two-dimensional hole system (2DHS) of extremely high quality (with hole density p=1.6x10^{10} cm^{-2} and mobility \mu=0.8x10^6 cm^2/Vs) that, as the 2DHS is continuously tilted with respect to the…
We construct a generalized Laughlin-liquid wave function and a variational electron solid wave function when the magnetic field is tilted. The energy of the liquid state is evaluated by Monte Carlo methods while the energy of the solid…
The magneto resistance of a narrow single quantum well is spectacularly different from the usual behavior. At filling factors 2/3 and 3/5 we observe large and sharp maxima in the longitudinal resistance instead of the expected minima. The…
The normal-state Hall effect and magnetoresisitance (MR) have been measured in the quasi-2D heavy fermion superconductor CeCoIn_5. In the non-Fermi liquid region where the reistivity rho_xx exhibits an almost perfect T-linear dependence,…
Motivated by the discovery of extremely low energy collective modes in the fractional quantum Hall effect (Kang, Pinczuk {\em et al.}), with energies below the Zeeman energy, we study theoretically the spin reversed excitations for…