Related papers: Two-dimensional electrons occupying multiple valle…
We report measurements of the spin susceptibility in dilute (rs up to 10) AlAs two-dimensional (2D) electrons occupying a single conduction-band valley with an anisotropic in-plane Fermi contour, characterized by longitudinal and transverse…
We study broken symmetry states at integer Landau level fillings in multivalley quantum Hall systems whose low energy dispersions are anisotropic. When the Fermi surface of individual pockets lacks twofold rotational symmetry, like in…
Measurements on a two-dimensional electron system confined to an AlAs quantum well reveal that for a given electron density the valley susceptibility, defined as the change in valley population difference per unit strain, is enhanced as the…
We study two-component electrons in the lowest Landau level at total filling factor $\nu _T=1/2$ with anisotropic mass tensors and principal axes rotated by $\pi/2$ as realized in Aluminum Arsenide (AlAs) quantum wells. Combining exact…
The Zeeman splitting and the underlying value of the g-factor for conduction band electrons in GaAs/Al_xGa_{1-x}As quantum wells have been measured by spin-beat spectroscopy based on a time-resolved Kerr rotation technique. The experimental…
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 system. As the two-dimensional density is reduced, the valley…
Two-dimensional hexagonal materials such as transition metal dichalcogenides exhibit valley degrees of freedom, offering fascinating potential for valley-based quantum computing and optoelectronics. In nonlinear optics, the K and K' valleys…
We investigate the wave functions, spectrum, and g-factor anisotropy of low-energy electrons confined to self-assembled, pyramidal InAs quantum dots (QDs) subject to external magnetic and electric fields. We present the construction of…
Metal-oxide-semiconductor field-effect transistors (MOSFET's) using atomic-layer-deposited (ALD) Al$_2$O$_3$ as the gate dielectric are fabricated on the Si/Si$_{1-x}$Ge$_x$ heterostructures. The low-temperature carrier density of a…
We report magneto-transport measurements on high-mobility two-dimensional electron systems (2DESs) confined in In_0.75Ga_0.25As/In_0.75Al_0.25As single quantum wells. Several quantum Hall states are observed in a wide range of temperatures…
Two-dimensional electrons confined to GaAs quantum wells are hallmark platforms for probing electron-electron interaction. Many key observations have been made in these systems as sample quality improved over the years. Here, we present a…
The rich magneto-electronic properties of AA-bottom-top (bt) bilayer silicene are investigated using a generalized tight-binding model. The electronic structure exhibits two pairs of oscillatory energy bands in which the lowest conduction…
Bilayer two-dimensional electron systems formed by a thin barrier in the GaAs buffer of a standard heterostructure were investigated by magnetotransport measurements. In magnetic fields oriented parallel to the electron layers, the…
From spin resonance of two-dimensional (2D) conduction electrons in a modulation doped SiGe/Si/SiGe quantum well structure we find a 2D anisotropy of both the line broadening (dephasing time) and the g-factor. We show that these can be…
We have previously shown that the Stoner instability 2D has unconventional behavior: it is strongly first order but features a susceptibility which diverges at the transition point. Here, we analyze the Stoner transition for two-dimensional…
DC-electric field, being screened in 3D semiconductors, normally decays monotonically in space. Experimental studies of the DC electric field screening in Si-SiO$_2$ multiple quantum wells by electric field induced optical second-harmonic…
The low-temperature magnetoresistance of parabolic quantum wells displays pronounced minima between integer filling factors. Concomitantly the Hall effect exhibits overshoots and plateau-like features next to well-defined ordinary quantum…
We review recent experimental results indicating the band flattening and Landau level merging at the chemical potential in strongly-correlated two-dimensional (2D) electron systems. In ultra-clean, strongly interacting 2D electron system in…
Frictional drag measurements revealing anomalously large dissipation at the transition between the weakly- and strongly-coupled regimes of a bilayer two-dimensional electron system at total Landau level filling factor $\nu_T =1$ are…
In modern GaAs/Al$_x$Ga$_{1-x}$As heterostructures with record high mobilities, a two-dimensional electron gas (2DEG) in a quantum well is provided by two remote donor $\delta$-layers placed on both sides of the well. Each $\delta$-layer is…