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Author Gol’tsman, G. N.; Smirnov, K. V.
Title (up) Electron-phonon interaction in a two-dimensional electron gas of semiconductor heterostructures at low temperatures Type Journal Article
Year 2001 Publication Jetp Lett. Abbreviated Journal Jetp Lett.
Volume 74 Issue 9 Pages 474-479
Keywords 2DEG, AlGaAs/GaAs heterostructures
Abstract Theoretical and experimental works devoted to studying electron-phonon interaction in the two-dimensional electron gas of semiconductor heterostructures at low temperatures in the case of strong heating in an electric field under quasi-equilibrium conditions and in a quantizing magnetic field perpendicular to the 2D layer are considered.
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ISSN 0021-3640 ISBN Medium
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Notes По итогам проектов российского фонда фундаментальных исследований. Проект РФФИ # 98-02-16897 Электрон-фононное взаимодействие в двумерном электронном газе полупроводниковых гетероструктур при низких температурах Approved no
Call Number Serial 1541
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Author Sergeev, A.; Mitin, V.
Title (up) 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 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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ISSN 0163-1829 ISBN Medium
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Notes Approved no
Call Number Serial 307
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Author Ptitsina, N. G.; Chulkova, G. M.; Il’in, K. S.; Sergeev, A. V.; Pochinkov, F. S.; Gershenzon, E. M.; Gershenson, M. E.
Title (up) Electron-phonon interaction in disordered metal films: The resistivity and electron dephasing rate Type Journal Article
Year 1997 Publication Phys. Rev. B Abbreviated Journal Phys. Rev. B
Volume 56 Issue 16 Pages 10089-10096
Keywords disordered metal films, electron-phonon interaction, electron dephasing rate, resistivity
Abstract The temperature dependence of the resistance of films of Al, Be, and NbC with small values of the electron mean free path l=1.5–10nm has been measured at 4.2–300 K. The resistance of all the films contains a T2 contribution that is proportional to the residual resistance; this contribution has been attributed to the interference between the elastic electron scattering and the electron-phonon scattering. Fitting the data to the theory of the electron-phonon-impurity interference (M. Yu. Reiser and A. V. Sergeev, Zh. Eksp. Teor. Fiz. 92, 224 (1987) [Sov. Phys. JETP 65, 1291 (1987)]), we obtain constants of interaction of the electrons with transverse phonons, and estimate the contribution of this interaction to the electron dephasing rate in thin films of Au, Al, Be, Nb, and NbC. Our estimates are in a good agreement with the experimental data on the inelastic electron-phonon scattering in these films. This indicates that the interaction of electrons with transverse phonons controls the electron-phonon relaxation rate in thin-metal films over a broad temperature range.
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ISSN 0163-1829 ISBN Medium
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Notes Approved no
Call Number Serial 1766
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Author Gousev, Y. P.; Semenov, A. D.; Gol'tsman, G. N.; Sergeev, A. V.; Gershenzon, E. M.
Title (up) Electron-phonon interaction in disordered NbN films Type Journal Article
Year 1994 Publication Phys. B Condens. Mat. Abbreviated Journal Phys. B Condens. Mat.
Volume 194-196 Issue Pages 1355-1356
Keywords NbN films
Abstract Electron-phonon interaction time has been investigated in disordered films of NbN. A temperatures below 5.5 K tau_eph ~ T -1"6 which is attributed to the renormalisation of phonon spectrum in thin films.
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ISSN 0921-4526 ISBN Medium
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Notes Approved no
Call Number Serial 1649
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Author Gershenzon, E. M.; Gershenzon, M. E.; Goltsman, G. N.; Lulkin, A.; Semenov, A. D.; Sergeev, A. V.
Title (up) Electron-phonon interaction in ultrathin Nb films Type Journal Article
Year 1990 Publication Sov. Phys. JETP Abbreviated Journal Sov. Phys. JETP
Volume 70 Issue 3 Pages 505-511
Keywords Nb films
Abstract A study was made of the heating of electrons in normal resistive states of superconducting thin Nb films. The directly determined relaxation time of the resistance of a sample and the rise of the electron temperature were used to find the electron-phonon interaction time rep,, The dependence of rep, on the mean free path of electrons re,, a 1-'demonstrated, in agreement with the theoretical predictions, that the contribution of the inelastic scattering of electrons by impurities to the energy relaxation process decreased at low temperatures and the observed temperature dependence rep, a T 2 was due to a modification of the phonon spectrum in thin fllms.

1. Much new information on the electron-phonon interaction time?;,, in thin films of normal metals and superconductors has been published recently. This information has been obtained mainly as a result of two types of measurement. One includes experiments on weak electron localization investigated by the method of quantum interference corrections to the conductivity of disordered conductors, which can be used to find the relaxation time T, of the phase of the electron wave function. In the absence of the scattering of electrons by paramagnetic impurities the relaxation time T, is associated with the most effective process of energy relaxation: T;= TL+ rep;, where T,, is the electronelectron relaxation time. At low temperatures, when the dependence T; a T is exhibited by thin disordered films, the dominant channel is that of the electron-electron relaxation and there is a lower limit to the temperature range in which rep, can be investigated.
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Call Number Serial 241
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Author Yang, Y.; Fedorov, G.; Shafranjuk, S. E.; Klapwijk, T. M.; Cooper, B. K.; Lewis, R. M.; Lobb, C. J.; Barbara, P.
Title (up) Electronic transport and possible superconductivity at Van Hove singularities in carbon nanotubes Type Journal Article
Year 2015 Publication Nano Lett. Abbreviated Journal Nano Lett.
Volume 15 Issue 12 Pages 7859-7866
Keywords carbon nanotubes, CNT, tunable superconductivity, van Hove singularities
Abstract Van Hove singularities (VHSs) are a hallmark of reduced dimensionality, leading to a divergent density of states in one and two dimensions and predictions of new electronic properties when the Fermi energy is close to these divergences. In carbon nanotubes, VHSs mark the onset of new subbands. They are elusive in standard electronic transport characterization measurements because they do not typically appear as notable features and therefore their effect on the nanotube conductance is largely unexplored. Here we report conductance measurements of carbon nanotubes where VHSs are clearly revealed by interference patterns of the electronic wave functions, showing both a sharp increase of quantum capacitance, and a sharp reduction of energy level spacing, consistent with an upsurge of density of states. At VHSs, we also measure an anomalous increase of conductance below a temperature of about 30 K. We argue that this transport feature is consistent with the formation of Cooper pairs in the nanotube.
Address Department of Physics, Georgetown University , Washington, District of Columbia 20057, United States
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ISSN 1530-6984 ISBN Medium
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Notes PMID:26506109; Suuplementary info (attached to pdf) DOI: 10.1021/acs.nanolett.5b02564 Approved no
Call Number Serial 1782
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Author Kardakova, A. I.; Coumou, P. C. J. J.; Finkel, M. I.; Morozov, D. V.; An, P. P.; Goltsman, G. N.; Klapwijk, T. M.
Title (up) Electron–phonon energy relaxation time in thin strongly disordered titanium nitride films Type Journal Article
Year 2015 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.
Volume 25 Issue 3 Pages 1-4
Keywords TiN MKID
Abstract We have measured the energy relaxation times from the electron bath to the phonon bath in strongly disordered TiN films grown by atomic layer deposition. The measured values of τ eph vary from 12 to 91 ns. Over a temperature range from 3.4 to 1.7 K, they follow T -3 temperature dependence, which are consistent with values of τ eph reported previously for sputtered TiN films. For the most disordered film, with an effective elastic mean free path of 0.35 nm, we find a faster relaxation and a stronger temperature dependence, which may be an additional indication of the influence of strong disorder on a superconductor.
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ISSN 1051-8223 ISBN Medium
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Notes Approved no
Call Number Serial 1296
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Author Sergeev, A.; Karasik, B. S.; Ptitsina, N. G.; Chulkova, G. M.; Il'in, K. S.; Gershenzon, E. M.
Title (up) Electron–phonon interaction in disordered conductors Type Journal Article
Year 1999 Publication Phys. Rev. B Condens. Matter Abbreviated Journal Phys. Rev. B Condens. Matter
Volume 263-264 Issue Pages 190-192
Keywords disordered conductors, electron-phonon interaction
Abstract The electron–phonon interaction is strongly modified in conductors with a small value of the electron mean free path (impure metals, thin films). As a result, the temperature dependencies of both the inelastic electron scattering rate and resistivity differ significantly from those for pure bulk materials. Recent complex measurements have shown that modified dependencies are well described at K by the electron interaction with transverse phonons. At helium temperatures, available data are conflicting, and cannot be described by an universal model.
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ISSN 0921-4526 ISBN Medium
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Notes Approved no
Call Number Serial 1765
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Author Smirnov, K. V.; Ptitsina, N. G.; Vakhtomin, Y. B.; Verevkin, A. A.; Gol’tsman, G. N.; Gershenzon, E. M.
Title (up) Energy relaxation of two-dimensional electrons in the quantum Hall effect regime Type Journal Article
Year 2000 Publication JETP Lett. Abbreviated Journal JETP Lett.
Volume 71 Issue 1 Pages 31-34
Keywords 2DEG, GaAs/AlGaAs heterostructures
Abstract The mm-wave spectroscopy with high temporal resolution is used to measure the energy relaxation times τe of 2D electrons in GaAs/AlGaAs heterostructures in magnetic fields B=0–4 T under quasi-equilibrium conditions at T=4.2 K. With increasing B, a considerable increase in τe from 0.9 to 25 ns is observed. For high B and low values of the filling factor ν, the energy relaxation rate τ −1e oscillates. The depth of these oscillations and the positions of maxima depend on the filling factor ν. For ν>5, the relaxation rate τ −1e is maximum when the Fermi level lies in the region of the localized states between the Landau levels. For lower values of ν, the relaxation rate is maximum at half-integer values of τ −1e when the Fermi level is coincident with the Landau level. The characteristic features of the dependence τ −1e (B) are explained by different contributions of the intralevel and interlevel electron-phonon transitions to the process of the energy relaxation of 2D electrons.
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ISSN 0021-3640 ISBN Medium
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Notes http://jetpletters.ru/ps/899/article_13838.shtml (“Энергетическая релаксация двумерных электронов в области квантового эффекта Холла”) Approved no
Call Number Serial 1559
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Author Gershenzon, E. M.; Gol'tsman, G. N.; Kagane, M. L.
Title (up) Energy spectrum of acceptors in germanium and its response to a magnetic field Type Journal Article
Year 1977 Publication Sov. Phys. JETP Abbreviated Journal Sov. Phys. JETP
Volume 45 Issue 4 Pages 769-776
Keywords p-Ge, photoconductivity, energy spectrum, magnetic field
Abstract We investigated the spectrum of the submillimeter photoconductivity of p-Ge at helium temperatures and the effects of a magnetic field up to 40 kOe on the spectrum. A large number of lines of transitions between the excited states of the acceptors was observed, some of the lines were identified, and the energies of a number of spectral levels B, Al, Ga, In, and TI in Ge were identified. The results are compared with calculations and with experimental data obtained from the spectra of the photoexcitation of the ground state of the impurities. Using one transition as an example, we discuss the splitting of the excited states of acceptors in the magnetic field and under uniaxial compression.
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Notes Approved no
Call Number Serial 1727
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Author Gershenzon, E. M.; Gol'tsman, G.; Ptitsina, N. G.
Title (up) Energy spectrum of free excitons in germanium Type Journal Article
Year 1973 Publication JETP Lett. Abbreviated Journal JETP Lett.
Volume 18 Issue 3 Pages 93
Keywords Ge, free excitons, energy spectrum
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Call Number Serial 1734
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Author Gershenzon, E. M.; Gol'tsman, G. N.; Elant'ev, A. I.
Title (up) Energy spectrum of the donors in GaAs and Ge and its reaction to a magnetic field Type Journal Article
Year 1977 Publication Sov. Phys. JETP Abbreviated Journal Sov. Phys. JETP
Volume 45 Issue 3 Pages 555-565
Keywords Ge, GaAs, magnetic field, donors, energy spectrum
Abstract The spectrum of the submillimeter photoconductivity of n-GaAs and n-Ge in a magnetic field up to 60 kOe at helium temperatures was investigated. A large number of lines due to transitions between excited states of the donors have been investigated, and the measurement results were used to determine a number of levels of the energy spectrum in a wide range of magnetic fields. For GaAs, these data are compared with calculations of the energy spectrum of the hydrogen atom in magnetic fields up to -2X lo9 Oe. For the donors in Ge, the energy spectrum is investigated at different orientations of the magnetic field relative to the crystallographic axes (H 11 [loo], [I 1 I], [110]), and these results are also compared with the corresponding calculations.
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Notes Approved no
Call Number Serial 1728
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Author Beck, M.; Klammer, M.; Lang, S.; Leiderer, P.; Kabanov, V. V.; Gol'tsman, G. N.; Demsar, J.
Title (up) Energy-gap dynamics of superconducting NbN thin films studied by time-resolved terahertz spectroscopy Type Journal Article
Year 2011 Publication Phys. Rev. Lett. Abbreviated Journal Phys. Rev. Lett.
Volume 107 Issue 17 Pages 4
Keywords NbN thin film, energy gap dynamics
Abstract Using time-domain terahertz spectroscopy we performed direct studies of the photoinduced suppression and recovery of the superconducting gap in a conventional BCS superconductor NbN. Both processes are found to be strongly temperature and excitation density dependent. The analysis of the data with the established phenomenological Rothwarf-Taylor model enabled us to determine the bare quasiparticle recombination rate, the Cooper pair-breaking rate and the electron-phonon coupling constant, λ=1.1±0.1, which is in excellent agreement with theoretical estimates.
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Call Number RPLAB @ gujma @ Serial 641
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Author Voevodin, E. I.; Gershenzon, E. M.; Goltsman, G. N.; Ptitsina, N. G.
Title (up) 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 1692
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Author Klapwijk, T. M.; Semenov, A. V.
Title (up) Engineering physics of superconducting hot-electron bolometer mixers Type Journal Article
Year 2017 Publication IEEE Trans. THz Sci. Technol. Abbreviated Journal IEEE Trans. THz Sci. Technol.
Volume 7 Issue 6 Pages 627-648
Keywords HEB mixers
Abstract Superconducting hot-electron bolometers are presently the best performing mixing devices for the frequency range beyond 1.2 THz, where good-quality superconductor-insulator-superconductor devices do not exist. Their physical appearance is very simple: an antenna consisting of a normal metal, sometimes a normal-metal-superconductor bilayer, connected to a thin film of a narrow short superconductor with a high resistivity in the normal state. The device is brought into an optimal operating regime by applying a dc current and a certain amount of local-oscillator power. Despite this technological simplicity, its operation has found to be controlled by many different aspects of superconductivity, all occurring simultaneously. A core ingredient is the understanding that there are two sources of resistance in a superconductor: a charge-conversion resistance occurring at a normal-metal-superconductor interface and a resistance due to time-dependent changes of the superconducting phase. The latter is responsible for the actual mixing process in a nonuniform superconducting environment set up by the bias conditions and the geometry. The present understanding indicates that further improvement needs to be found in the use of other materials with a faster energy relaxation rate. Meanwhile, several empirical parameters have become physically meaningful indicators of the devices, which will facilitate the technological developments.
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ISSN 2156-342X ISBN Medium
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Notes Approved no
Call Number Serial 1292
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