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Related papers: Highly enhanced thermopower in two-dimensional ele…

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Using a new second derivative technique and thermometers which enable us to determine the local electron temperature in a mesoscopic metallic sample, we have obtained quantitative measurements of the low temperature field and temperature…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 D. A. Dikin , S. Jung , V. Chandrasekhar

Electric field gradient effects induced by an asymmetrically in-plane shaped GaAs/AlGaAs modulation-doped structures of various design are investigated within 4-300 K temperature range. It is demonstrated that current-voltage…

Previous experimental work on a two-dimensional (2D) electron gas in a Si-on-sapphire device led to the conclusion that both conductivity and phonon drag thermopower $S^g$ are affected to the same relative extent by weak localization. The…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 A. Miele , R. Fletcher , E. Zaremba , Y. Feng , C. T. Foxon , J. J. Harris

The usually negligibly small thermoelectric effects in superconducting heterostructures can be boosted dramatically due to the simultaneous effect of spin splitting and spin filtering. Building on an idea of our earlier work [Phys. Rev.…

Mesoscale and Nanoscale Physics · Physics 2015-02-20 P. Machon , M. Eschrig , W. Belzig

We present the thermopower of EuCd2P2, a material which exhibits a large resistivity peak with significant magnetic field dependence in the temperature range of 10-25 K. In the same region we observe a highly unusual behavior of the…

The thermodynamic potential of an ideal nonrelativistic gas of two-dimensional electrons in crossed uniform magnetic and electric fields is constructed. For low temperatures and very weak electric fields, it is shown that the Hall…

Condensed Matter · Physics 2007-05-23 Choon-Lin Ho , V. R. Khalilov , Chi Yang

In the present work, we report the experimental thermopower ($\alpha$) data for ZnV$_{2}$O$_{4}$ compound in the high temperature range 300-600 K. The value of $\alpha$ is found to be $\sim$184 and $\sim$126 $\mu$V/K at $\sim$300 and…

Materials Science · Physics 2016-09-30 Saurabh Singh , R. K. Maurya , Sudhir K. Pandey

We have used a field-penetration method to measure thermodynamic compressibility of a moderately interacting two-dimensional electron system ($r_{s}$ $\approx$ 0.5-3) in a three terminal GaAs/AlGaAs device, fabricated with an epitaxial…

Strongly Correlated Electrons · Physics 2009-09-29 S. C. Dultz , B. Alavi , H. W. Jiang

In many strongly correlated electron metals the thermoelectric power has a non-monotonic temperature dependence and values that are orders of magnitude larger than for elemental metals. Kelvin proposed a particularly simple expression for…

Strongly Correlated Electrons · Physics 2015-04-01 J. Kokalj , Ross. H. McKenzie

The observation of coherent quantum transport phenomena in metals and semiconductors is limited by the eventual loss of phase coherence of the conducting electrons. We use the weak localization effect to measure the low-temperature…

Mesoscale and Nanoscale Physics · Physics 2010-08-27 M. Eshkol , E. Eisenberg , M. Karpovski , A. Palevski

Measuring the temperature of a two-dimensional electron gas at temperatures of a few mK is a challenging issue, which standard thermometry schemes may fail to tackle. We propose and analyze a nongalvanic thermometer, based on a quantum…

Mesoscale and Nanoscale Physics · Physics 2012-06-20 S. Gasparinetti , M. J. Martínez-Pérez , S. de Franceschi , J. P. Pekola , F. Giazotto

We demonstrate the electrical and optical control of ferromagnetism in semiconductor heterostructures at high temperatures of 100-117 K. The heterostructures consist of Mn delta-doped GaAs and p-type AlGaAs, where the overlap of the hole…

Materials Science · Physics 2007-05-23 Ahsan M. Nazmul , S. Kobayashi , S. Sugahara , M. Tanaka

Thermoelectric power, electrical conductivity, and high field Hall effect were studied over a broad temperature range in ferromagnetic Ga(1-x)Mn(x)As epitaxial layers (0.015<x<0.06). Thermoelectric power analysis gives the information about…

Experimental results on the metal-insulator transition and related phenomena in strongly interacting two-dimensional electron systems are discussed. Special attention is given to recent results for the strongly enhanced spin susceptibility,…

Strongly Correlated Electrons · Physics 2016-11-18 A. A. Shashkin , S. V. Kravchenko

We report the experimental realization of a non-galvanic, primary thermometer capable of measuring the electron temperature of a two-dimensional electron gas with negligible thermal load. Such a thermometer consists of a quantum dot whose…

Mesoscale and Nanoscale Physics · Physics 2013-12-13 P. Torresani , M. J. Martínez-Pérez , S. Gasparinetti , J. Renard , G. Biasiol , L. Sorba , F. Giazotto , S. De Franceschi

We report electrical conductance and thermopower measurements on InAs nanowires synthesized by chemical vapor deposition. Gate modulation of the thermopower of individual InAs nanowires with diameter around 20nm is obtained over T=40 to…

Mesoscale and Nanoscale Physics · Physics 2013-03-18 Yuan Tian , Mohammed R. Sakr , Jesse M. Kinder , Dong Liang , Michael J. MacDonald , Richard L. J. Qiu , Hong-Jun Gao , Xuan P. A. Gao

We measure transport through a Ga[Al]As heterostructure at temperatures between 0.1 K and 30 K. Increasing the temperature enhances the electron-electron scattering rate and viscous effects in the two-dimensional electron gas arise. To…

We review some of our recent experimental studies on low-carrier concentration, mesoscopic two-dimensional electron gases (m2DEGs). The m2DEGs show a range of striking characteristics including a complete avoidance of the strongly localised…

Mesoscale and Nanoscale Physics · Physics 2016-11-21 Vijay Narayan , Michael Pepper , David Ritchie

The thermoelectric effect is the generation of an electrical voltage from a temperature gradient in a solid material due to the diffusion of free charge carriers from hot to cold. Identifying materials with large thermoelectric response is…

Strongly Correlated Electrons · Physics 2018-05-31 Brian Skinner , Liang Fu

We report the discovery of two-dimensional electron gas (2DEG) at the surface of thermoelectric material In$_4$Se$_3$ by angle-resolved photoemission spectroscopy. The observed 2DEG exhibits a nearly isotropic band dispersion with a…

Mesoscale and Nanoscale Physics · Physics 2016-06-22 K. Fukutani , T. Sato , P. V. Galiy , K. Sugawara , T. Takahashi