21 papers
Anomalous giant piezoresistance in AlAs 2D electrons with anti-dot lattices
O. Gunawan, T. Gokmen, Y. P. Shkolnikov +2
An AlAs two-dimensional electron system patterned with an anti-dot lattice exhibits a giant piezoresistance (GPR) effect, with a sign opposite to the piezoresistance observed in th…
Tuning of the spin-orbit interaction in two-dimensional GaAs holes via strain
B. Habib, J. Shabani, E. P. De Poortere +2
We report direct measurements of the spin-orbit interaction induced spin-splitting in a modulation-doped GaAs two-dimensional hole system as a function of anisotropic, in-plane str…
Spin-valley phase diagram of the two-dimensional metal-insulator transition
O. Gunawan, T. Gokmen, K. Vakili +3
Using symmetry breaking strain to tune the valley occupation of a two-dimensional (2D) electron system in an AlAs quantum well, together with an applied in-plane magnetic field to…
AlAs 2D electrons in an antidot lattice: Electron pinball with elliptical Fermi contours
O. Gunawan, E. P. De Poortere, M. Shayegan
We report ballistic transport measurements in a two-dimensional electron system confined to an AlAs quantum well and patterned with square antidot lattices of period 0.6, 0.8…
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…
Role of density imbalance in an interacting bilayer hole system
E. Tutuc, S. Melinte, E. P. De Poortere +2
We study interacting GaAs hole bilayers in the limit of zero tunneling. When the layers have equal densities, we observe a phase coherent bilayer quantum Hall (QH) state at total f…