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The long-missing polarization-induced two-dimensional hole gas is finally observed in undoped gallium nitride quantum wells. Experimental results provide unambiguous proof that a 2D hole gas in GaN grown on AlN does not need acceptor…

Materials Science · Physics 2019-10-23 Reet Chaudhuri , Samuel James Bader , Zhen Chen , David A. Muller , Huili , Xing , Debdeep Jena

Two-dimensional electron gases (2DEGs) can form at the surface of oxides and semiconductors or in carefully designed quantum wells and interfaces. Depending on the shape of the confining potential, 2DEGs may experience a finite electric…

Nonequilibrium transport measurements in mesoscopic quasi-ballistic 2D electron systems show an enhancement in the differential conductance around the Fermi energy. At very low temperatures, such a zero-bias anomaly splits, leading to a…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Arindam Ghosh , Matthew Wright , Christophe Siegert , Michael Pepper , Ian Farrer , Chris Ford , David Ritchie

A two-dimensional (2D) electron gas formed in a modulation-doped GaAs/AlGaAs single quantum well undergoes a first-order transition when the first excited subband is occupied with electrons, as the Fermi level is tuned into resonance with…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 A. R. Goñi , U. Haboeck , C. Thomsen , K. Eberl , F. A. Reboredo , C. R. Proetto , F. Guinea

We have studied the transition from two to three dimensions in a low temperature weakly interacting $^6$Li Fermi gas. Below a critical atom number, $N_{2D}$, only the lowest transverse vibrational state of a highly anisotropic oblate…

Quantum Gases · Physics 2011-03-16 P. Dyke , E. D. Kuhnle , S. Whitlock , H. Hu , M. Mark , S. Hoinka , M. Lingham , P. Hannaford , C. J. Vale

We study one-dimensional transport in focused-ion-beam written in-plane-gate transistors on III-V heterostructures at moderately low temperatures at zero bias without any external magnetic field applied. In accordance with a recent proposal…

Mesoscale and Nanoscale Physics · Physics 2015-06-25 Ralf D. Tscheuschner , Andreas D. Wieck

Fermi gases in two dimensions display a surprising collective behavior originating from the head-on carrier collisions. The head-on processes dominate angular relaxation at not-too-high temperatures $T\ll T_F$ owing to the interplay of…

Mesoscale and Nanoscale Physics · Physics 2019-09-18 Patrick J Ledwith , Haoyu Guo , Andrey V Shytov , Leonid Levitov

We report low temperature magnetotransport measurements on a high mobility (\mu=325,000 cm^2/V sec) 2D electron system on a H-terminated Si(111) surface. While low magnetic field data indicate a six-fold valley degenerate system, we observe…

Mesoscale and Nanoscale Physics · Physics 2014-01-29 Tomasz M. Kott , Binhui Hu , S. H. Brown , B. E. Kane

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…

Applied Physics · Physics 2025-01-27 Joseph E. Dill , Chuan F. C. Chang , Debdeep Jena , Huili Grace Xing

We have measured magnetotransport of the two-dimensional electron gas in a Hall bar geometry in the presence of small carrier density gradients. We find that the longitudinal resistances measured at both sides of the Hall bar interchange by…

Mesoscale and Nanoscale Physics · Physics 2016-08-16 L. A. Ponomarenko , D. T. N. de Lang , A. de Visser , V. A. Kulbachinskii , G. B. Galiev , H. Künzel , A. M. M. Pruisken

We investigate the electronic dispersion and transport properties of graphene/WSe$_{2}$ heterostructures in the presence of a proximity-induced spin-orbit coupling $\lambda_{v}$, sublattice potential $\Delta$, and an off-resonant circularly…

Mesoscale and Nanoscale Physics · Physics 2023-07-07 M. Zubair , P. Vasilopoulos , M. Tahir

We study how the non-Fermi-liquid two-phase state reveals itself in transport properties of high-mobility Si-MOSFETs. We have found features in zero-field transport, magnetotransport, and thermodynamic spin magnetization in a 2D correlated…

Strongly Correlated Electrons · Physics 2016-06-28 L. A. Morgun , A. Yu. Kuntsevich , V. M. Pudalov

Using recent insights obtained in heavy fermion physics on the thermodynamic singularity structure associated with quantum phase transitions, we present here an experimental strategy to establish if the zero-temperature transition in the…

Strongly Correlated Electrons · Physics 2007-05-23 B. Hosseinkhani , J. Zaanen

A population imbalance at different valleys of an electronic system lowers its effective rotational symmetry. We introduce a technique to measure such imbalance - a valley polarization - that exploits the unique fingerprints of this…

The 2-D electron system (2DES) in Si metal-oxide field-effect transistors (MOSFETS) consists of two distinct electron fluids interacting with each other. We calculate the total energy as a function of the density $n$, and the spin…

Strongly Correlated Electrons · Physics 2007-05-23 M. W. C. Dharma-wardana , François Perrot

The goal of this paper is to highlight several issues which are most crucial for the understanding of the ``metal-insulator transition'' in two dimensions. We discuss some common problems in interpreting experimental results on high…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 B. L. Altshuler , D. L. Maslov , V. M. Pudalov

Screening of an external random potential by a two dimensional (2D) Fermi liquid may be strongly dependent on the degree of its polarization. This is considered as a possible mechanism for the observed strong magnetoresistance of the 2D…

Strongly Correlated Electrons · Physics 2009-10-31 Igor F. Herbut

We report an experimental study of the quantum corrections to the longitudinal conductivity and the Hall coefficient of a low mobility, high density two-dimensional two-dimensional electron gas in a AlGaAs/GaAs/AlGaAs quantum well in a wide…

Mesoscale and Nanoscale Physics · Physics 2015-06-24 Vincent Thomas Francois Renard , O. A. Tkachenko , Ze Don Kvon , E. B. Olshanetsky , A. I. Toropov , J. C Portal

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…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 O. Gunawan , Y. P. Shkolnikov , K. Vakili , T. Gokmen , E. P. De Poortere , M. Shayegan

Undoped Si-SiGe two-dimensional electron gas (2DEG) provide an ideal platform for hosting quantum-dot spin-qubits owing enhanced spin dephasing times and compatibility with standard CMOS technology. The strained Si quantum well reduces the…