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We present thermopower measurements on a high electron mobility two-dimensional electron gas (2DEG) in a thin suspended membrane.We show that the small dimension of the membrane substantially reduces the thermal conductivity compared to…

Mesoscale and Nanoscale Physics · Physics 2015-06-03 M. Schmidt , G. Schneider , Ch. Heyn , A. Stemmann , W. Hansen

We measure the temperature of a 2D electron gas in GaAs from the thermopower of a one-dimensional ballistic constriction, using the Mott relation to confirm the calibration from the electrical conductance. Under hot electron conditions,…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 N. J. Appleyard , J. T. Nicholls , M. Y. Simmons , W. R. Tribe , M. Pepper

We report experimental observation of an unexpectedly large thermopower in mesoscopic two-dimensional (2D) electron systems on GaAs/AlGaAs heterostructures at sub-Kelvin temperatures and zero magnetic field. Unlike conventional non-magnetic…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 Srijit Goswami , Christoph Siegert , Matthias Baenninger , Arindam Ghosh , Michael Pepper , Ian Farrer , David A. Ritchie

We present measurements of the cooling length $\ell_E$ for hot electrons in a GaAs-based high mobility two-dimensional electron gas (2DEG). The thermal measurements are performed on a long 60 $\mu$m-wide channel, which is Joule-heated at…

Mesoscale and Nanoscale Physics · Physics 2026-01-21 A. K. Jain , J. T. Nicholls , S. N. Holmes , G. Jaliel , C. Chen , I. Farrer , D. A. Ritchie

The longitudinal thermopower of ultra-high mobility two-dimensional electrons has been measured at both zero magnetic field and at high fields in the compressible metallic state at filling factor $\nu = 3/2$ and the incompressible…

Mesoscale and Nanoscale Physics · Physics 2013-05-29 W. E. Chickering , J. P. Eisenstein , L. N. Pfeiffer , K. W. West

We present thermal and electrical transport measurements of low-density (10$^{14}$ m$^{-2}$), mesoscopic two-dimensional electron systems (2DESs) in GaAs/AlGaAs heterostructures at sub-Kelvin temperatures. We find that even in the…

We report thermopower ($S$) and electrical resistivity ($\rho_{2DES}$) measurements in low-density (10$^{14}$ m$^{-2}$), mesoscopic two-dimensional electron systems (2DESs) in GaAs/AlGaAs heterostructures at sub-Kelvin temperatures. We…

Strongly Correlated Electrons · Physics 2015-03-20 Vijay Narayan , M. Pepper , J. Griffths , H. Beere , F. Sfigakis , G. Jones , D. Ritchie , A. Ghosh

The thermoelectric power of nondegenerate Kane semiconductors with due regard for the electron and phonon heating, and their thermal and mutual drags is investigated. The electron spectrum is taken in the Kane two-band form. It is shown…

Statistical Mechanics · Physics 2009-11-07 M. M. Babaev , T. M. Gassym , M. Tas , M. Tomak

We study the low-temperature thermopower of micron sized, free-standing membranes containing a two-dimensional electron system. Suspended membranes of 320 nm thickness including a high electron mobility structure in Hall bar geometry of 34…

Mesoscale and Nanoscale Physics · Physics 2015-06-03 M. Schmidt , G. Schneider , Ch. Heyn , A. Stemmann , W. Hansen

The diffusion of energy that is locally deposited into two-dimensional electron gases by Joule heating generates transverse voltages across devices with broken symmetry. For mesoscopic structures characterized by device dimensions…

Mesoscale and Nanoscale Physics · Physics 2014-11-19 Stephan Rojek , Jürgen König

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 develop ion-ion pair potentials for Al, Na and K for densities and temperatures relevant to the warm-dense-matter (WDM) regime. Furthermore, we emphasize non-equilibrium states where the ion temperature $T_i$ differs from the electron…

Materials Science · Physics 2015-03-19 Louis Harbour , M. W. Chandre Dharma-wardana , Dennis D. Klug , Laurent J. Lewis

Using as a thermometer the temperature dependent magneto-transport of a two-dimensional electron gas, we find that effective temperature scales with current as $T_{\rm e} \sim I^a$, where $a=0.4 \pm 2\%$ in the {\it Shubnikov de-Haas}…

Condensed Matter · Physics 2009-10-28 Edmond Chow , H. P. Wei , S. M. Girvin , M. Shayegan

We demonstrate that kinetic coefficients related to thermoelectric properties of the two dimensional electron gas in the diffusive regime are strongly influenced by electron-electron interaction. As an example we consider the thermoelectric…

Strongly Correlated Electrons · Physics 2015-05-30 V. T. Dolgopolov , A. Gold

We theoretically study phonon-drag contribution to the thermoelectric power and hot-electron energy-loss rate in a Rashba spin-orbit coupled two-dimensional electron system (2DES) in the Bloch-Gruneisen (BG) regime. We assume that electrons…

Mesoscale and Nanoscale Physics · Physics 2013-06-12 Tutul Biswas , Tarun Kanti Ghosh

We present measurements of the energy relaxation length scale $\ell$ in two-dimensional electron gases (2DEGs). A temperature gradient is established in the 2DEG by means of a heating current, and then the elevated electron temperature…

Mesoscale and Nanoscale Physics · Physics 2015-07-16 Jordan Billiald , Dirk Backes , Jürgen König , Ian Farrer , David Ritchie , Vijay Narayan

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 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

The thermopower in a two-dimensional semimetal existing in HgTe quantum wells 18-21 nm thick has been studied experimentally and theoretically for the first time. It has been found theoretically and experimentally that the thermopower has…

Mesoscale and Nanoscale Physics · Physics 2018-12-26 E. B. Olshanetsky , Z. D. Kvon , M. V. Entin , L. I. Magarill , A. Levin , G. M. Gusev , N. N. Mikhailov

We present thermopower $S$ and resistance $R$ measurements on GaAs-based mesoscopic two-dimensional electron gases (2DEGs) as functions of the electron density $n_s$. At high $n_s$ we observe good agreement between the measured $S$ and…

Mesoscale and Nanoscale Physics · Physics 2015-04-27 Vijay Narayan , Eugene Kogan , Chris Ford , Michael Pepper , Moshe Kaveh , Jonathan Griffiths , Geb Jones , Harvey Beere , Dave Ritchie
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