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We present magnetotransport measurements on freely suspended two-dimensional electron gases from AlGaAs/GaAs heterostructures. The technique to realize such devices relies on a specially MBE grown GaAs/AlGaAs-heterostructure including a…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 R. H. Blick , F. G. Monzon , W. Wegscheider , M. Bichler , F. Stern , M. L. Roukes

In this paper, density functional theory calculations are used to explore the electronic and atomic reconstruction at interfaces between III-III/I-V oxides. In particular, at these interfaces, two dimensional electron gases (2DEGs) with…

Materials Science · Physics 2012-06-06 Valentino R. Cooper

Pure spin currents are measured in micron-wide channels of GaAs two-dimensional electron gas (2DEG). Spins are injected and detected using quantum point contacts, which become spin polarized at high magnetic field. High sensitivity to the…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 S. M. Frolov , A. Venkatesan , W. Yu , W. Wegscheider , J. A. Folk

Thermoelectric (TE) materials achieve localised conversion between thermal and electric energies, and the conversion efficiency is determined by a figure of merit zT. Up to date, two-dimensional electron gas (2DEG) related TE materials hold…

We present thermoelectric power and resistivity measurements in the ferromagnet UGe$_2$ as a function of temperature and magnetic field. At low temperature, huge quantum oscillations are observed in the thermoelectric power as a function of…

Strongly Correlated Electrons · Physics 2016-05-04 A. Palacio Morales , A. Pourret , G. Knebel , G. Bastien , V. Taufour , D. Aoki , H. Yamagami , J. Flouquet

Many-body interactions in transition-metal oxides give rise to a wide range of functional properties, such as high-temperature superconductivity, colossal magnetoresistance, or multiferroicity. The seminal recent discovery of a…

The electronic response of a two-dimensional (2D) electron system represents a key quantity in discussing one-electron properties of electrons in semiconductor heterojunctions, on the surface of liquid helium and in copper-oxide planes of…

Materials Science · Physics 2009-10-31 A. Bergara , J. M. Pitarke , P. M. Echenique

We report on a new class of magnetoresistance oscillations observed in a high-mobility two-dimensional electron gas (2DEG) in GaAs-Al$_x$Ga$_{1-x}$As heterostructures. Appearing in a weak magnetic field ($B<$ 0.3 T) and only in a narrow…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 M. A. Zudov , I. V. Ponomarev , A. L. Efros , R. R. Du , J. A. Simmons , J. L. Reno

Electrostatic gates are of paramount importance for the physics of devices based on high-mobility two-dimensional electron gas (2DEG) since they allow depletion of electrons in selected areas. This field-effect gating enables the…

Mesoscale and Nanoscale Physics · Physics 2015-09-23 K. Bennaceur , B. A. Schmidt , S. Gaucher , D. Laroche , M. P. Lilly , J. L. Reno , K. W. West , L. N. Pfeiffer , G. Gervais

An ultradense 2D electron system can be realized by adsorbing PH$_3$ precursor molecules onto an atomically clean Si surface, followed by epitaxial Si overgrowth. By controlling the PH$_3$ coverage the carrier density of such system can…

Condensed Matter · Physics 2007-05-23 M. A. Zudov , C. L. Yang , R. R. Du , T. -C. Shen , J. -Y. Ji , J. S. Kline , J. R. Tucker

A technically simple and physically clear method is suggested for the direct measurement of brightness temperature of two-dimensional electron gas (2DEG) in the channel of a high electron mobility transistor (HEMT). The usage of the method…

Mesoscale and Nanoscale Physics · Physics 2016-05-04 A. M. Korolev , V. M. Shulga , O. G. Turutanov , V. I. Shnyrkov

Two-dimensionally confined electrons showing unusually large thermopower (S) have attracted attention as a potential approach for developing high performance thermoelectric materials. However, enhanced S has never been observed in electric…

We report results regarding the electron transport in vertical quasi-2D layered 1T-TaS2 charge-density-wave devices. The low-frequency noise spectroscopy was used as a tool to study changes in the cross-plane electrical characteristics of…

We report measurements of dm/dn in Si MOSFET, where m is the magnetization of the two-dimensional electron gas and n is its density. We extended the density range of measurements from well in the metallic to deep in the insulating region.…

Strongly Correlated Electrons · Physics 2011-03-08 M. Reznikov , A. Yu. Kuntsevich , N. Teneh , V. M. Pudalov

We use dynamic scanning capacitance microscopy (DSCM) to image compressible and incompressible strips at the edge of a Hall bar in a two-dimensional electron gas (2DEG) in the quantum Hall effect (QHE) regime. This method gives access to…

Mesoscale and Nanoscale Physics · Physics 2012-09-17 M. E. Suddards , A. Baumgartner , M. Henini , C. J. Mellor

We report direct experimental evidence that the insulating phase of a disordered, yet strongly interacting two-dimensional electron system (2DES) becomes unstable at low temperatures. As the temperature decreases, a transition from…

Mesoscale and Nanoscale Physics · Physics 2008-01-15 M. Baenninger , A. Ghosh , M. Pepper , H. E. Beere , I. Farrer , D. A. Ritchie

We report electrical conductivity $\sigma$ measurements on a range of two-dimensional electron gases (2DEGs) of varying linear extent. Intriguingly, at low temperatures ($T$) and low carrier density ($n_{\mathrm{s}}$) we find the behavior…

Mesoscale and Nanoscale Physics · Physics 2016-05-25 Dirk Backes , Richard Hall , Michael Pepper , Harvey Beere , David Ritchie , Vijay Narayan

Correlated electron states in high mobility two-dimensional electron systems (2DESs), including charge density waves and microemulsion phases intermediate between a Fermi liquid and Wigner crystal, are predicted to exhibit complex local…

Mesoscale and Nanoscale Physics · Physics 2014-11-11 Matthew Pelliccione , John Bartel , Adam Sciambi , Loren Pfeiffer , Ken West , David Goldhaber-Gordon

In a high mobility two-dimensional electron gas (2DEG) in a GaAs/AlGaAs quantum well we observe a strong magnetoresistance. In lowering the electron density the magnetoresistance gets more pronounced and reaches values of more than 300%. We…

Mesoscale and Nanoscale Physics · Physics 2015-05-20 L. Bockhorn , P. Barthold , D. Schuh , W. Wegscheider , R. J. Haug

We measure thermodynamic magnetization of a low-disordered, strongly correlated two-dimensional electron system in silicon. Pauli spin susceptibility is observed to grow critically at low electron densities - behavior that is characteristic…

Strongly Correlated Electrons · Physics 2007-05-23 S. V. Kravchenko , A. A. Shashkin , S. Anissimova , A. Venkatesan , M. R. Sakr , V. T. Dolgopolov , T. M. Klapwijk