342 citations · 987 across the 16 of their papers we have counts for
14 papers · 1 filter
Effective mass suppression upon complete spin-polarization in an isotropic two-dimensional electron system
T. Gokmen, Medini Padmanabhan, K. Vakili +2
We measure the effective mass (m*) of interacting two-dimensional electrons confined to a 4.5 nm-wide AlAs quantum well. The electrons in this well occupy a single out-of-plane con…
Parallel Magnetic Field Tuning of Valley Splitting in AlAs Two-Dimensional Electrons
T. Gokmen, Medini Padmanabhan, O. Gunawan +4
We demonstrate that, in a quasi-two-dimensional electron system confined to an AlAs quantum well and occupying two conduction-band minima (valleys), a parallel magnetic field can c…
Valley polarization and susceptibility of composite fermions around nu=3/2
N. C. Bishop, M. Padmanabhan, K. Vakili +3
We report magnetotransport measurements of fractional quantum Hall states in an AlAs quantum well around Landau level filling factor nu = 3/2, demonstrating that the quasiparticles…
Two-dimensional electrons occupying multiple valleys in AlAs
M. Shayegan, E. P. De Poortere, O. Gunawan +3
Two-dimensional electrons in AlAs quantum wells occupy multiple conduction-band minima at the X- points of the Brillouin zone. These valleys have large effective mass and g-factor…
Zeeman splitting of interacting two-dimensional electrons with two effective masses
K. Vakili, E. Tutuc, M. Shayegan
We have realized an AlAs two-dimensional electron system in which electrons occupy conduction-band valleys with different Fermi contours and effective masses. In the quantum Hall r…
Dependence of persistent gaps at Landau level crossings on relative spin
K. Vakili, T. Gokmen, O. Gunawan +3
We report measurements of the quantum Hall state energy gap at avoided crossings between Landau levels originating from different conduction band valleys in AlAs quantum wells. The…
High-mobility AlAs quantum wells with out-of-plane valley occupation
K. Vakili, Y. P. Shkolnikov, E. Tutuc +3
Employing state-of-the-art molecular beam epitaxy techniques to grow thin, modulation-doped AlAs quantum wells, we have achieved a low temperature mobility of 5.5 m/Vs with out…
Valley susceptibility of an interacting two-dimensional electron system
O. Gunawan, Y. P. Shkolnikov, K. Vakili +3
We report direct measurements of the valley susceptibility, the change of valley population in response to applied symmetry-breaking strain, in an AlAs two-dimensional electron sys…
Spin-dependent resistivity at transitions between integer quantum Hall states
K. Vakili, Y. P. Shkolnikov, E. Tutuc +3
The longitudinal resistivity at transitions between integer quantum Hall states in two-dimensional electrons confined to AlAs quantum wells is found to depend on the spin orientati…
Giant low-temperature piezoresistance effect in AlAs two-dimensional electrons
Y. P. Shkolnikov, K. Vakili, E. P. De Poortere +1
We present piezoresistance measurements in modulation doped AlAs quantum wells where the two-dimensional electron system occupies two conduction band valleys with elliptical Fermi…
Low-temperature, in situ tunable, uniaxial stress measurements in semiconductors using a piezoelectric actuator
M. Shayegan, K. Karrai, Y. P. Shkolnikov +3
We demonstrate the use of a piezoelectric actuator to apply, at low temperatures, uniaxial stress in the plane of a two-dimensional electron system confined to a modulation-doped A…
Spin susceptibility of two-dimensional electrons in narrow AlAs quantum wells
K. Vakili, Y. P. Shkolnikov, E. Tutuc +2
We report measurements of the spin susceptibility in dilute two-dimensional electrons confined to a 45 wide AlAs quantum well. The electrons in this well occupy an out-of-plane…
Realization of an Interacting Two-Valley AlAs Bilayer System
K. Vakili, Y. P. Shkolnikov, E. Tutuc +2
By using different widths for two AlAs quantum wells comprising a bilayer system, we force the X-point conduction-band electrons in the two layers to occupy valleys with different…
Magnetic Field Induced Spin Polarization of AlAs Two-dimensional Electrons
E. P. De Poortere, E. Tutuc, Y. P. Shkolnikov +2
Two-dimensional (2D) electrons in an in-plane magnetic field become fully spin polarized above a field B_P, which we can determine from the in-plane magnetoresistance. We perform s…