Related papers: Ultraclean two-dimensional hole systems with mobil…
We demonstrate a method of making a very shallow, gateable, undoped 2-dimensional electron gas. We have developed a method of making very low resistivity contacts to these structures and systematically studied the evolution of the mobility…
Gate-tunable high-mobility InSb/In_{1-x}Al_{x}Sb quantum wells (QWs) grown on GaAs substrates are reported. The QW two-dimensional electron gas (2DEG) channel mobility in excess of 200,000 cm^{2}/Vs is measured at T=1.8K. In asymmetrically…
We have studied ballistic transport in a 1D channel formed using surface gate techniques on a back-gated, high-mobility, bilayer 2D hole system. At millikelvin temperatures, robust conductance quantization is observed in the quantum wire…
We present quantitative measurements and calculations of the spin-orbit induced zero-magnetic-field spin-splitting in two-dimensional (2D) hole systems in modulation-doped GaAs (311)A quantum wells. The results show that the splitting is…
High-quality C-doped p-type AlGaAs heterostructures with mobilities exceeding 150 000 cm$^2$/Vs are investigated by low-temperature magnetotransport experiments. We find features of the fractional quantum Hall effect as well as a highly…
We perform detailed magnetotransport studies on two-dimensional electron gases (2DEGs) formed in undoped Si/SiGe heterostructures in order to identify the electron mobility limiting mechanisms in this increasingly important materials…
We study molecular beam epitaxially grown, undoped Al$_{x}$Ga$_{1-x}$Sb/InAs/AlSb quantum wells with different buffer and barrier designs and varying quantum well width. The highest mobilities were achieved with Al$_{0.33}$Ga$_{0.67}$Sb…
We investigate the disorder properties of two-dimensional hole gases in Ge/SiGe heterostructures grown on Ge wafers, using thick SiGe barriers to mitigate the influence of the semiconductor-dielectric interface. Across several…
We describe a technique to fabricate closely spaced electron-hole bilayers in GaAs-AlGaAs heterostructures. Our technique incorporates a novel method for making shallow contacts to a low density ($<10^{11}cm^{-2}$) 2-dimensional electron…
We study two dimensional hole systems confined to GaAs quantum wells grown on the (311)A surface of GaAs substrates. Such samples exhibit an in-plane mobility anisotropy. At constant 2D hole density, we vary the symmetry of the quantum well…
Two-dimensional (2D) semiconductors show great potential to sustain Moore's law in the era of ultra-scaled electronics. However, their scalable applications are severely constrained by low hole mobility. In this work, we take 2D-GaAs as a…
We report a backgated InAs/GaSb double quantum well device grown on GaSb substrate. The use of the native substrate allows for high materials quality with electron mobility in excess of 500,000 cm2/Vs at sheet charge density of 8x1011 cm-2…
InSb is one of the promising candidates to realize a topological state through proximity induced superconductivity in a material with strong spin-orbit interactions. In two-dimensional systems, thin barriers are needed to allow strong…
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…
We develop a two-carrier Hall effect model fitting algorithm to analyze temperature-dependent magnetotransport measurements of a high-density ($\sim4\times10^{13}$ cm$^2$/Vs) polarization-induced two-dimensional hole gas (2DHG) in a GaN/AlN…
Development of new, high quality functional materials has been at the forefront of condensed matter research. The recent advent of two-dimensional black phosphorus has greatly enriched the material base of two-dimensional electron systems.…
We report measurements and calculations of the spin-subband depopulation, induced by a parallel magnetic field, of dilute GaAs two-dimensional (2D) hole systems. The results reveal that the shape of the confining potential dramatically…
We report on the growth and characterization of a new Diluted Magnetic Semiconductor (DMS) heterostructure that presents a Two-Dimensional Electron Gas (2DEG) with a carrier density $n \sim 1.08 \times 10^{12} cm^{-2}$ and a mobility $\mu…
Quantum transport measurements are performed in gate-defined, high-quality, two-dimensional hole and electron systems in an undoped InSb quantum well. For both polarities, the carrier systems show tunable spin-orbit interaction as extracted…
GaAs-based two-dimensional electron gases (2DEGs) show a wealth of remarkable electronic states, and serve as the basis for fast transistors, research on electrons in nanostructures, and prototypes of quantum-computing schemes. All these…