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The unsymmetric confinement of the electrons in a typical 2-dimensional electron gas (2DEG) breaks the full cubic symmetry of the in-plane transport properties. A rigorous invariance of the transport under rotation by pi/2 about the cubic…
Gate-controllable two dimensional systems with in-plane modulation of properties could serve as highly tunable effective media. Intuitively, such systems may bring novel functionality provided that the period of the lateral modulation is…
Topological superconductivity can be engineered in semiconductors with strong spin-orbit interaction coupled to a superconductor. Experimental advances in this field have often been triggered by the development of new hybrid material…
Modulation doped GaAs-AlGaAs quantum well based structures are usually used to achieve very high mobility 2-dimensional electron (or hole) gases. Usually high mobilities ($>10^{7}{\rm{cm}^{2}\rm{V}^{-1}\rm{s}^{-1}}$) are achieved at high…
The temperature dependence of the coherence time of hole spins confined in self-assembled (In,Ga)As/GaAs quantum dots is studied by spin mode-locking and spin echo techniques. Coherence times limited to about a \mu s are measured for…
The two dimensional electron gas (2DEG) in moderate magnetic fields in ultra-clean AlAs-GaAs heterojunctions exhibits transport anomalies suggestive of a compressible, anisotropic metallic state. Using scaling arguments and Monte Carlo…
Recent theoretical results on transport in a two-dimensional disordered electron liquid with spin and isospin degrees of freedom are reviewed. A number of experimental features in temperature dependence of resistivity at low temperatures in…
We have studied spin dephasing in a high-mobility two-dimensional electron system (2DES), confined in a GaAs/AlGaAs quantum well grown in the [110] direction, using the resonant spin amplification (RSA) technique. From the characteristic…
Understanding, creating, and manipulating spin polarization of two-dimensional electron gases at complex oxide interfaces presents an experimental challenge. For example, despite almost a decade long research effort, the microscopic origin…
The Dresselhaus spin-orbit interaction (SOI) of a series of two-dimensional electron gases (2DEGs) hosted in GaAs/AlGaAs and InGaAs/GaAs (001) quantum wells (QWs) is measured by monitoring the precession frequency of the spins as a function…
Electrically detected electron spin resonance (EDESR) signals were acquired as a function of temperature in the 0.3-4.2 K temperature range in a AlGaAs/GaAs multiple quantum well sample at the filling factor at 5.7 T. In the particular…
We investigate high-mobility two-dimensional electron gases in AlGaAs heterostructures by employing Schottky-gate-dependent measurements of the samples' electron density and mobility. Surprisingly, we find that two different sample…
Experiments on a constant-density two-dimensional hole system in a GaAs quantum well reveal that the metallic behavior observed in the zero-magnetic-field temperature dependence of the resistivity depends on the symmetry of the confinement…
GaN and the heterostructures are attractive in condensed matter science and applications for electronic devices. We measure the electron transport in GaN/AlGaN field-effect transistors (FETs) at cryogenic temperature. We observe formation…
Tunneling conductance $G(T)$ through a constricted point contact is studied for the $\nu=2/3$ spin-singlet edges. Including spin-flip tunneling, Zeeman splitting and random magnetic impurities, we discuss the various crossovers of $G(T)$ as…
We have theoretically studied phonon-mediated spin-flip processes of electrons in a GaAs double quantum dot (DQD) holding two spins, under a phonon temperature gradient over the DQD. Transition rates of inter-dot phonon-assisted tunnel…
We present measurements of the energy relaxation length scale $\ell$ in two-dimensional electron gases (2DEGs). A temperature gradient is established in the 2DEG by means of a heating current, and then the elevated electron temperature…
A two-dimensional electron gas (2DEG) in two-valley semiconductors has two discrete degrees of freedom given by the spin and valley quantum numbers. We analyze the zero-temperature magnetic instabilities of two-valley semiconductors with…
We report on the fabrication and characterization of patterned high-mobility two-dimensional electron gases (2DEG) formed on SrTiO$_3$ (STO) substrate surfaces by hydrogen plasma exposure. The resulting devices consistently showed high…
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…