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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 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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Corporate Author Thesis
Publisher Place of Publication Editor
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 (up) 1612
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Author Il'in, K. S.; Karasik, B. S.; Ptitsina, N. G.; Sergeev, A. V.; Gol'tsman, G. N.; Gershenzon, E. M.; Pechen, E. V.; Krasnosvobodtsev, S. I.
Title Electron-phonon-impurity interference in thin NbC films: electron inelastic scattering time and corrections to resistivity Type Conference Article
Year 1996 Publication Czech. J. Phys. Abbreviated Journal Czech. J. Phys.
Volume 46 Issue S2 Pages 857-858
Keywords NbC films
Abstract Complex study of transport properties of impure NbC films with the electron mean free pathl=0.6–13 nm show the crucial role of the electron-phonon-impurity interference (EPII). In the temperature range 20–70 K we found the interference correction to resistivity proportional to T2 and to the residual resistivity of the film. Using the comprehensive theory of EPII, we determine the electron coupling with transverse phonons and calculate the electron inelastic scattering time. Direct measurements of the inelastic electron scattering time using a response to a high-frequency amplitude modulated cw radiation agree well with the theory.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0011-4626 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial (up) 1617
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Author Verevkin, A. I.; Ptitsina, N. G.; Chulkova, G. M.; Gol'tsman, G. N.; Gershenzon, E. M.; Yngvesson, K. S.
Title Electron energy relaxation in a 2D channel in AlGaAs-GaAs heterostructures under quasiequilibrium conditions at low temperatures Type Journal Article
Year 1995 Publication JETP Lett. Abbreviated Journal JETP Lett.
Volume 61 Issue 7 Pages 591-595
Keywords 2DEG, AlGaAs/GaAs heterostructures
Abstract The energy relaxation time of 2D electrons, Te, has been measured under quasiequilibrium conditions in AlGaAs—GaAs heterojunctions over the temperature range T= 1.5—20 K. At T> 4 K, Te depends only weakly on the temperature, while at T< 4 K 7;'(T) there is a dependence fr; lNT. A linear dependence 7: 1 (T) in the Bloch—-Grfineisen temperature region (T< 5 K) is unambiguous evidence that a piezoacoustic mechanism of an electron—phonon interaction is predominant in the inelastic scattering of electrons. The values of T6 in this temperature range agree very accurately with theoretical results reported by Karpus [Sov. Phys. Semicond. 22 (1988)]. At higher temperatures, where scat—tering by deformation acoustic phonons becomes substantial, there is a significant discrepancy between the experimental and theoretical re-sults.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial (up) 1624
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Author Varyukhin, S. V.; Zakharov, A. A.; Gershenzon, E. M.; Gol'tsman, G. N.; Ptitsina, N. G.; Chulkova, G. M.
Title Low energy excitation in La2CuO4 Type Journal Article
Year 1990 Publication Sverkhprovodimost': Fizika, Khimiya, Tekhnika Abbreviated Journal Sverkhprovodimost': Fizika, Khimiya, Tekhnika
Volume 3 Issue 5 Pages 832-837
Keywords metal-dielectric-La2CuO4, monocrystals
Abstract Measurements of transmission and photoconductivity spectra in submillimeter wave length range as well as of capacity C and conductivity G in the region of acoustic frequencies of metal-dielectric-La2CuO4 system at low temperatures are performed using La2CuO4 monocrystals. Optical spectra posses a threshold character, a sharp decrease of transmission and photocoductivity signal occurs in the energy region hν>1.5 MeV. C(ω,T) and G(ω, T) dependences have a universal form typical of Debye type relaxation processes. Relaxation time dependence is of thermoactivated character τ(T)∼exp(ξ/T) with the gap value ξ≅2 meV. It is assumed that excitations with characteristic energy of ∼2 meV exist in La2CuO4. A possible nature of the detected low-energy excitations is discussed.
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Notes Approved no
Call Number Serial (up) 1688
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Author Voevodin, E. I.; Gershenzon, E. M.; Goltsman, G. N.; Ptitsina, N. G.
Title Energy-spectrum of shallow acceptors in Ge deformed strongly by a uniaxial pressure Type Journal Article
Year 1989 Publication Sov. Phys. and Technics of Semiconductors Abbreviated Journal Sov. Phys. and Technics of Semiconductors
Volume 23 Issue 8 Pages 843-846
Keywords Ge, crystallography
Abstract Проведены исследования спектров фототермической ионизации мелких акцепторов (В, Аl) в Ge, предельно сжатом вдоль кристаллографической оси [100]. Из данных измерений с учетом теории построен энергетический спектр примесей. Показано, что энергии большого числа уровней четных и нечетных состояний хорошо соответствуют расчету, выполненному для примесей в анизотропном полупроводнике с параметром анизотропии γ=m∗⊥/m∗∥>1.
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Notes Энергетический спектр мелких акцепторов в сильно одноосно деформированном Ge Approved no
Call Number Serial (up) 1692
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