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Author Verevkin, A. A.; Ptitsina, N. G.; Chulcova, G. M.; Gol'Tsman, G. N.; Gershenzon, E. M.; Yngvesson, K. S.
Title Determination of the limiting mobility of a two-dimensional electron gas in AlxGa1-xAs/GaAs heterostructures and direct measurement of the energy relaxation time Type Journal Article
Year 1996 Publication Phys. Rev. B Condens. Matter. Abbreviated Journal Phys. Rev. B Condens. Matter.
Volume 53 Issue 12 Pages (down) R7592-R7595
Keywords 2DEG, AlGaAs/GaAs heterostructures
Abstract We present results for a method to measure directly the energy relaxation time (τe) for electrons in a single AlxGa1−xAs/GaAs heterojunction; measurements were performed from 1.6 to 15 K under quasiequilibrium conditions. We find τeαT−1 below 4 K, and τe independent of T above 4 K. We have also measured the energy-loss rate, ⟨Q⟩, by the Shubnikov-de Haas technique, and find ⟨Q⟩α(T3e−T3) for T<~4.2 K; Te is the electron temperature. The values and temperature dependence of τe and ⟨Q⟩ for T<4 K agree with calculations based on piezoelectric and deformation potential acoustic phonon scattering. At 4.2 K, we can also estimate the momentum relaxation time, τm, from our measured τe. This leads to a preliminary estimate of the phonon-limited mobility at 4.2 K of μ=3×107 cm2/Vs (ns=4.2×1011 cm−2), which agrees well with published numerical calculations, as well as with an earlier indirect estimate based on measurements on a sample with much higher mobility.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0163-1829 ISBN Medium
Area Expedition Conference
Notes PMID:9982274 Approved no
Call Number Serial 1612
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Author Sergeev, A.; Mitin, V.
Title Electron-phonon interaction in disordered conductors: Static and vibrating scattering potentials Type Journal Article
Year 2000 Publication Phys. Rev. B. Abbreviated Journal Phys. Rev. B.
Volume 61 Issue 9 Pages (down) 6041-6047
Keywords disordered conductors, scattering potential, electron-phonon interaction
Abstract Employing the Keldysh diagram technique, we calculate the electron-phonon energy relaxation rate in a conductor with the vibrating and static δ-correlated random electron-scattering potentials. If the scattering potential is completely dragged by phonons, this model yields the Schmid’s result for the inelastic electron-scattering rate τ−1e−ph. At low temperatures the effective interaction decreases due to disorder, and τ−1e−ph∝T4l (l is the electron mean-free path). In the presense of the static potential, quantum interference of numerous scattering processes drastically changes the effective electron-phonon interaction. In particular, at low temperatures the interaction increases, and τ−1e−ph∝T2/l. Along with an enhancement of the interaction, which is observed in disordered metallic films and semiconducting structures at low temperatures, the suggested model allows us to explain the strong sensitivity of the electron relaxation rate to the microscopic quality of a particular film.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0163-1829 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 307
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Author Romijn, J.; Klapwijk, T. M.; Renne, M. J.; Mooij, J. E.
Title Critical pair-breaking current in superconducting aluminum strips far below Tc Type Journal Article
Year 1982 Publication Phys. Rev. B Abbreviated Journal Phys. Rev. B
Volume 26 Issue 7 Pages (down) 3648-3655
Keywords superconducting nanowire
Abstract Critical currents of narrow, thin aluminum strips have been measured as a function of temperature. For the smallest samples uniformity of the current density is obtained over a large temperature range. Hence the intrinsic limit on the currentcarrying capacity of the superconductor was measured outside the Ginzburg-Landau -regime. The experimental values are compared with recent theoretical predictions by Kupriyanov and Lukichev. An approximate method of solving their equations is given, the results of which agree with the exact solution to within 1%. Experimental data are in excellent agreement with theoretical predictions. The absolute values agree if one assumes a ρl value of 4×10–16 Ωm2 with vF=1.3×106 m/s. This value for ρl is the same as that found from measurements of the anomalous skin effect but differs from values extracted from size-effect-limited resistivity.
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Notes Recommended by Klapwijk Approved no
Call Number Serial 925
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Author Santhanam, P.; Wind, S.; Prober, D. E.
Title Localization, superconducting fluctuations, and superconductivity in thin films and narrow wires of aluminum Type Journal Article
Year 1987 Publication Phys. Rev. B Abbreviated Journal Phys. Rev. B
Volume 35 Issue 7 Pages (down) 3188-3206
Keywords Al films; electron-phonon scattering; electron-electron scattering; Disordered structures; amorphous and glassy solids, Relaxation times and mean free paths, Galvanomagnetic and other magnetotransport effects
Abstract We report a comprehensive set of experiments on wide and narrow thin-film strips of aluminum which test the predictions of recent localization theory. The experiments on wide films in the two-dimensional regime confirm the theoretical predictions and also yield insight into inelastic mechanisms and spin-orbit scattering rates. Our extension of the existing theory for one-dimensional systems to include spin-orbit scattering and Maki-Thompson superconducting fluctuations is verified by the experiments. We find clear evidence for one-dimensional localization, with inferred inelastic rates identical to those in two-dimensional films. The prediction of the localization theory for a dimensional crossover from two-dimensional to one-dimensional behavior is also confirmed. We have reanalyzed the results of some previous experiments on thin films and narrow wires in light of these results.
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Notes Approved no
Call Number RPLAB @ gujma @ Serial 757
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Author Shah, Jagdeep; Pinczuk, A.; Gossard, A. C.; Wiegmann, W.
Title Energy-loss rates for hot electrons and holes in GaAs quantum wells Type Journal Article
Year 1985 Publication Phys. Rev. Lett. Abbreviated Journal Phys. Rev. Lett.
Volume 54 Issue Pages (down) 2045-2048
Keywords 2DEG, GaAs/AlGaAs, heat flow, electron-phonon, hole-phonon, carrier-phonon, interactions
Abstract We report the first direct determination of carrier-energy-loss rates in a semiconductor. These measurements provide fundamental insight into carrier-phonon interactions in semiconductors. Unexpectedly large differences are found in the energy-loss rates for electrons and holes in GaAs/AlGaAs quantum wells. This large difference results from an anomalously low electron-energy-loss rate, which we attribute to the presence of nonequilibrium optical phonons rather than the effects of reduced dimensionality or dynamic screening.
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Notes Approved no
Call Number Serial 633
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