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We present new results of the ``0.7'' 2(e^2)/h structure or quasi plateau in some of the most strongly confined point contacts so far reported. This strong confinement is obtained by a combination of shallow etching and metal gate…

The 0.7 (2e^2/h) conductance anomaly is studied in strongly confined, etched GaAs/GaAlAs quantum point contacts, by measuring the differential conductance as a function of source-drain and gate bias as well as a function of temperature. We…

Mesoscale and Nanoscale Physics · Physics 2009-01-20 A. Kristensen , H. Bruus , A. E. Hansen , J. B. Jensen , P. E. Lindelof , C. J. Marckmann , J. Nygard , C. B. Sorensen , F. Beuscher , A. Forchel , M. Michel

It has been shown within the Landauer single-channel approach that the presence of the 0.7 anomaly in the conductance of a ballistic microcontact and the respective plateau in the thermopower implies unusual pinning of the potential barrier…

Mesoscale and Nanoscale Physics · Physics 2015-06-15 O. A. Tkachenko , V. A. Tkachenko

We investigate near-equilibrium ballistic transport through a quantum point contact (QPC) along a GaAs/AlGaAs heterojunction with a transfer matrix technique, as a function of temperature and the shape of the potential barrier in the QPC.…

Mesoscale and Nanoscale Physics · Physics 2013-08-08 Alfredo X. Sánchez , Jean-Pierre Leburton

The temperature dependence of the conductance of a quantum point contact has been measured. The conductance as a function of the Fermi energy shows temperature-independent fixed points, located at roughly multiple integers of $e^{2}/h$.…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 V. Senz , T. Heinzel , T. Ihn , S. Lindemann , R. Held , K. Ensslin , W. Wegscheider , M. Bichler

The 0.7 conductance anomaly in the quantized conductance of trench etched GaAs quantum point contacts is studied experimentally. The temperature dependence of the anomaly measured with vanishing source-drain bias reveals the same activated…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 A. Kristensen , H. Bruus , A. Forchel , J. B. Jensen , P. E. Lindelof , M. Michel , J. Nygard , C. B. Sorensen

Electron transport in suspended and non-suspended GaAs point contacts (PCs) of different widths is experimentally studied. The superballistic contribution to the conductance, that demonstrates a distinctive quadratic dependence on the PC…

We report experimental studies of conductance and magnetoconductance of GaAs/AlGaAs quantum well structures where both wells and barriers are doped by acceptor impurity Be. Temperature dependence of conductance demonstrate a non-monotonic…

Disordered Systems and Neural Networks · Physics 2015-12-16 N. V. Agrinskaya , V. A. Berezovets , V. I. Kozub

Detailed experimental studies of the conductance of mesoscopic GaAs devices in the few-mode regime reveal a novel thermal effect: for temperatures up to at least 10 K the measured gate characteristics, i.e. conductance $G$ versus gate…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 A. E. Hansen , A. Kristensen , H. Bruus

In this study we used nonequilibrium simulation method to investigate the temperature dependent divergence of thermal conductivity in one dimensional momentum conserving system with asymmetric double well nearest-neighbor interaction…

Statistical Mechanics · Physics 2019-02-06 Archana G R , Debashis Barik

The temperature dependence of the diffuse scattering fine structure from disordered equiatomic CuAu was studied using {\it in situ} x-ray scattering. In contrast to Cu$_3$Au the diffuse peak splitting in CuAu was found to be relatively…

Condensed Matter · Physics 2012-08-27 O. Malis , K. F. Ludwig, , W. Schweika , G. E. Ice , C. J. Sparks

Very high precision measurements of the electron Lande g-factor in GaAs are presented using spin-quantum beat spectroscopy at low excitation densities and temperatures ranging from 2.6 to 300 K. In colligation with available data for the…

Materials Science · Physics 2009-05-26 J. Hübner , S. Döhrmann , D. Hägele , M. Oestreich

We report a detailed analytic and numerical study of electronic thermal conductivity in d-wave superconductors. We compare theory of the cross over at low temperatures from T-dependence to T^3-dependence for increasing temperature with…

Superconductivity · Physics 2009-11-11 Tomas Lofwander , Mikael Fogelstrom

We investigate the scaling properties of zero temperature conductances at integer quantum Hall plateau transitions in the lowest Landau band of a two-dimensional tight-binding model. Scaling is obeyed for all energy and system sizes with…

Disordered Systems and Neural Networks · Physics 2009-10-31 Xiashoa Wang , Qiming Li , C. M. Soukoulis

We consider a transmission of electrons through a two-dimensional ballistic point contact in the low-conductance regime below the 0.7-anomaly. The scattering of electrons by Friedel oscillations of charge density results in a contribution…

Mesoscale and Nanoscale Physics · Physics 2013-01-10 Tatiana Krishtop , Kirill Nagaev

For unpolarized electrons in a clean quantum wire, density functional theory reveals a thermally activated suppression of conductance. The activation temperature T_A grows slowly (roughly quadratically) with gate voltage due to pinning of…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 Kenji Hirose , Ned S. Wingreen

Contact resistivity rc of InP and GaAs based ohmic contacts was measured in the 4.2/300 K temperature range. Nonmonotonic dependences rc(T), with a minimum at temperature 50 K (150 K) for InP (GaAs) based contacts were obtained. The results…

We present measurements of the electron temperature using gate defined quantum dots formed in a GaAs 2D electron gas in both direct transport and charge sensing mode. Decent agreement with the refrigerator temperature was observed over a…

Mesoscale and Nanoscale Physics · Physics 2015-09-08 D. Maradan , L. Casparis , T. -M. Liu , D. E. F. Biesinger , C. P. Scheller , D. M. Zumbühl , J. Zimmerman , A. C. Gossard

Thermal conductance of a homogeneous 1D nonlinear lattice system with neareast neighbor interactions has recently been computationally studied in detail by Li et al [Eur. Phys. J. B {\bf 88}, 182 (2015)], where its power-law dependence on…

Statistical Mechanics · Physics 2017-06-07 Yunyun Li , Nianbei Li , Ugur Tirnakli , Baowen Li , Constantino Tsallis

We develop a temperature dependent empirical pseudopotential theory to study the electronic and optical properties of self-assembled quantum dots (QDs) at finite temperature. The theory takes the effects of both lattice expansion and…

Materials Science · Physics 2015-06-04 Jianping Wang , Ming Gong , Guang-Can Guo , Lixin He
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