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Smirnov, K. V.; Ptitsina, N. G.; Vakhtomin, Y. B.; Verevkin, A. A.; Gol’tsman, G. N.; Gershenzon, E. M. |
Title |
Energy relaxation of two-dimensional electrons in the quantum Hall effect regime |
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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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0021-3640 |
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http://jetpletters.ru/ps/899/article_13838.shtml (“Энергетическая релаксация двумерных электронов в области квантового эффекта Холла”) |
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1559 |
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Sergeev, A.; Semenov, A.; Trifonov, V.; Karasik, B.; Gol'tsman, G.; Gershenzon, E. |
Title |
Heat transfer in YBaCuO thin film/sapphire substrate system |
Type |
Journal Article |
Year |
1994 |
Publication |
J. Supercond. |
Abbreviated Journal |
J. Supercond. |
Volume |
7 |
Issue |
2 |
Pages |
341-344 |
Keywords |
YBCO films |
Abstract |
The thermal boundary resistance at the YBaCuO thin film/Al2O3 substrate interface was investigated. The transparency for thermal phonons incident on the interface as well as for phonons moving from the substrate was determined. We have measured a transient voltage response of current-biased films to continuously modulated radiation. The observed knee in the modulation frequency dependence of the response reflects the crossover from the diffusion regime to the contact resistance regime of the heat transfer across the interface. The values of transparency were independently deduced both from the phonon escape time and from the time of phonon return to the film which were identified with peculiarities in the frequency dependence. The results are much more consistent with the acoustic mismatch theory than the diffuse mismatch model. |
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0896-1107 |
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1647 |
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Sergeev, A.; Karasik, B. S.; Ptitsina, N. G.; Chulkova, G. M.; Il'in, K. S.; Gershenzon, E. M. |
Title |
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 |
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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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0921-4526 |
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1765 |
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Author ![sorted by Author field, descending order (down)](img/sort_desc.gif) |
Sergeev, A. V.; Semenov, A. D.; Kouminov, P.; Trifonov, V.; Goghidze, I. G.; Karasik, B. S.; Gol’tsman, G. N.; Gershenzon, E. M. |
Title |
Transparency of a YBa2Cu3O7-film/substrate interface for thermal phonons measured by means of voltage response to radiation |
Type |
Journal Article |
Year |
1994 |
Publication |
Phys. Rev. B Condens. Matter. |
Abbreviated Journal |
Phys. Rev. B Condens. Matter. |
Volume |
49 |
Issue |
13 |
Pages |
9091-9096 |
Keywords |
YBCO films |
Abstract |
The transparency of a film/substrate interface for thermal phonons was investigated for YBa2Cu3O7 thin films deposited on MgO, Al2O3, LaAlO3, NdGaO3, and ZrO2 substrates. Both voltage response to pulsed-visible and to continuously modulated far-infrared radiation show two regimes of heat escape from the film to the substrate. That one dominated by the thermal boundary resistance at the film/substrate interface provides an initial exponential decay of the response. The other one prevailing at longer times or smaller modulation frequencies causes much slower decay and is governed by phonon diffusion in the substrate. The transparency of the boundary for phonons incident from the film on the substrate and also from the substrate on the film was determined separately from the characteristic time of the exponential decay and from the time at which one regime was changed to the other. Taking into account the specific heat of optical phonons and the temperature dependence of the group velocity of acoustic phonons, we show that the body of experimental data agrees with acoustic mismatch theory rather than with the model that assumes strong diffusive scattering of phonons at the interface. |
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0163-1829 |
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PMID:10009690 |
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1648 |
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Sergeev, A. V.; Aksaev, E. E.; Gogidze, I. G.; Gol’tsman, G. N.; Semenov, A. D.; Gershenzon, E. M. |
Title |
Thermal boundary resistance at YBaCuO film-substrate interface |
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Conference Article |
Year |
1993 |
Publication |
Phonon Scattering in Condensed Matter VII. Springer Series in Solid-State Sciences |
Abbreviated Journal |
Phonon Scattering in Condensed Matter VII. Springer Series in Solid-State Sciences |
Volume |
112 |
Issue |
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Pages |
405-406 |
Keywords |
YBCO films |
Abstract |
The nanosecond voltage response of YBaCuo films on Al2O3, MgO and ZrO2 substrates to electromagnetic radiation of millimeter and visible ranges has been investigated. The analysis of experimental conditions for Al2O3 and MgO substrates shows that the resistance change is monitored by the Kapitza boundary shift of temperature during the temporal interval ~ 100 ns limited by the time of phonon return from a substrate into a film. The observed exponential voltage decay is described by the phonon escape time which is proportional to the film thickness and is weakly temperature dependent. |
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Meissner, M.; Pohl, R. O. |
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Seventh International Conference, Cornell University, Ithaca, New York, August 3-7, 1992 |
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1665 |
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Semenov, A. D.; Sergeev, A. V.; Kouminov, P.; Goghidze, I. G.; Heusinger, M. A.; Nebosis, R. S.; Gol'tsman, G. N.; Gershenzon, E. M.; Renk, K. F. |
Title |
Transparency of YBCO film/substrate interfaces for thermal phonons determined by photoresponse measurements |
Type |
Conference Article |
Year |
1993 |
Publication |
Proc. 1st European Conf. on Appl. Supercond. |
Abbreviated Journal |
Proc. 1st European Conf. on Appl. Supercond. |
Volume |
2 |
Issue |
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Pages |
1443-1446 |
Keywords |
YBCO HTS detectors |
Abstract |
Direct measurements of the thermal boundary resistance were performed by means of the stationary method. In this approach the temperature of an electrically heated film is controlled by its dc resistance while an additional film on the same substrate is used as a thermometer monitoring substrate temperature. The temperature field in the substrate is then calculated to deduce the Kapitza temperature step at the interface between the heated strip and the substrate. The main statement of all afore-said papers is that experimental values of the thermal boundary resistance are too large to be explained by the acoustic mismatch model. In this paper we investigate transparency of YBaCuO film/substrate interfaces for thermal phonons by means of photoresponse measurements. We show that our data are in reasonable agreement with the acoustic mismatch theory. |
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Freyhardt, H. C. |
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3-88355-197-X |
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1st European conference on applied superconductivity |
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1661 |
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Semenov, A. D.; Gousev, Y. P.; Renk, K. F.; Voronov, B. M.; Gol'tsman, G. N.; Gershenzon, E. M.; Schwaab, G.W.; Feinaugle, R. |
Title |
Noise characteristics of a NbN hot-electron mixer at 2.5 THz |
Type |
Journal Article |
Year |
1997 |
Publication |
IEEE Trans. Appl. Supercond. |
Abbreviated Journal |
IEEE Trans. Appl. Supercond. |
Volume |
7 |
Issue |
2 |
Pages |
3572-3575 |
Keywords |
NbN HEB mixers |
Abstract |
The noise temperature of a NbN phonon cooled hot-electron mixer has been measured at a frequency of 2.5 THz for various operating conditions. We obtained for optimal operation a double sideband mixer noise temperature of /spl ap/14000 K and a system conversion loss of /spl ap/23 dB at intermediate frequencies up to 1 GHz. The dependences of the mixer noise temperature on the bias voltage, local oscillator power, and intermediate frequency were consistent with the phenomenological description based on the effective temperature approximation. |
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1051-8223 |
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1594 |
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Semenov, A. D.; Gousev, Y. P.; Nebosis, R. S.; Renk, K. F.; Yagoubov, P.; Voronov, B. M.; Gol’tsman, G. N.; Syomash, V. D.; Gershenzon, E. M. |
Title |
Heterodyne detection of THz radiation with a superconducting hot‐electron bolometer mixer |
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Journal Article |
Year |
1996 |
Publication |
Appl. Phys. Lett. |
Abbreviated Journal |
Appl. Phys. Lett. |
Volume |
69 |
Issue |
2 |
Pages |
260-262 |
Keywords |
NbN HEB mixers |
Abstract |
We report on the use of a superconducting hot‐electron bolometer mixer for heterodyne detection of terahertz radiation. Radiation with a wavelength of 119 μm was coupled to the mixer, a NbN microbridge, by a hybrid quasioptical antenna consisting of an extended hyperhemispherical lens and a planar logarithmic spiral antenna. We found, at an intermediate frequency of 1.5 GHz, a system double side band noise temperature of ≊40 000 K and conversion losses of 25 dB. We also discuss the possibilities of further improvement of the mixer performance. |
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0003-6951 |
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no |
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1610 |
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Semenov, A. D.; Gol’tsman, G. N.; Gogidze, I. G.; Sergeev, A. V.; Gershenzon, E. M.; Lang, P. T.; Renk, K. F. |
Title |
Subnanosecond photoresponse of a YBaCuO thin film to infrared and visible radiation by quasiparticle induced suppression of superconductivity |
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Journal Article |
Year |
1992 |
Publication |
Appl. Phys. Lett. |
Abbreviated Journal |
Appl. Phys. Lett. |
Volume |
60 |
Issue |
7 |
Pages |
903-905 |
Keywords |
YBCO HTS detectors |
Abstract |
We observed subnanosecond photoresponse of a structured superconducting YBa2Cu3O7−δ thin film to infrared and visible radiation. We measured the voltage response of a current biased film (thickness 700 Å) in a resistive state to radiation pulses. From our results we conclude a response time of about 90 ps and a responsivity of about 4×1010 Ω/J. We attribute the response to Cooper pair breaking and suppression of the superconducting energy gap induced by nonequilibrium quasiparticles. |
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0003-6951 |
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Call Number |
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1672 |
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Author ![sorted by Author field, descending order (down)](img/sort_desc.gif) |
Semenov, A. D.; Goghidze, I. G.; Gol’tsman, G. N.; Sergeev, A. V.; Gershenzon, E. M. |
Title |
Evidence for the spectral dependence of nonequilibrium picosecond photoresponse of YBaCuO thin films |
Type |
Journal Article |
Year |
1993 |
Publication |
Appl. Phys. Lett. |
Abbreviated Journal |
Appl. Phys. Lett. |
Volume |
63 |
Issue |
5 |
Pages |
681-683 |
Keywords |
YBCO HTS detectors, nonequilibrium |
Abstract |
The transient voltage photoresponse of current biased YBaCuO thin films to 20 ps laser pulses of 0.63 and 1.54 μm wavelengths is measured for temperatures around the superconducting transition region. The fast picosecond decay of the response is followed by a slow nanosecond relaxation which is associated with the bolometric effect. The magnitude of the fast component of the response varies in proportion to the square root of wavelength that plausibly reflects multiplication processes of photoexcited electrons via electron–electron scattering and interaction with high energy phonons. |
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0003-6951 |
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1655 |
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