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Author Sergeev, A. V.; Semenov, A. D.; Kouminov, P.; Trifonov, V.; Goghidze, I. G.; Karasik, B. S.; Gol’tsman, G. N.; Gershenzon, E. M. url  doi
openurl 
  Title Transparency of a YBa2Cu3O7-film/substrate interface for thermal phonons measured by means of voltage response to radiation Type Journal Article
  Year (up) 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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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0163-1829 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:10009690 Approved no  
  Call Number Serial 1648  
Permanent link to this record
 
 
Author Gousev, Y. P.; Semenov, A. D.; Gol'tsman, G. N.; Sergeev, A. V.; Gershenzon, E. M. url  doi
openurl 
  Title Electron-phonon interaction in disordered NbN films Type Journal Article
  Year (up) 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.  
  Address  
  Corporate Author Thesis  
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  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0921-4526 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1649  
Permanent link to this record
 
 
Author Gol'tsman, G. N.; Karasik, B. S.; Okunev, O. V.; Dzardanov, A. L.; Gershenzon, E. M.; Ekstrom, H.; Jacobsson, S.; Kollberg, E. url  doi
openurl 
  Title NbN hot electron superconducting mixers for 100 GHz operation Type Journal Article
  Year (up) 1995 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.  
  Volume 5 Issue 2 Pages 3065-3068  
  Keywords NbN HEB mixers  
  Abstract NbN is a promising superconducting material for hot-electron superconducting mixers with an IF bandwidth larger than 1 GHz. In the 1OO GHz frequency range, the following parameters were obtained for 50 /spl Aring/ thick NbN films at 4.2 K: receiver noise temperature (DSB) /spl sim/1000 K; conversion loss /spl sim/10 dB; IF bandwidth /spl sim/1 GHz; and local oscillator power /spl sim/1 /spl mu/W. An increase of the critical current of the NbN film, increased working temperature, and a better mixer matching may allow a broader IF bandwidth up to 2 GHz, reduced conversion losses down to 3-5 dB and a receiver noise temperature (DSB) down to 200-300 K.  
  Address  
  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 1051-8223 ISBN Medium  
  Area Expedition Conference  
  Notes About LO power required Approved no  
  Call Number Serial 255  
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Author Ptitsina, N. G.; Chulkova, G. M.; Gershenzon, E. M. openurl 
  Title Influence of the interference of electron-phonon and electron-impurity scattering on the conductivity of unordered Nb films Type Journal Article
  Year (up) 1995 Publication JETP Abbreviated Journal JETP  
  Volume 80 Issue 5 Pages 960-964  
  Keywords  
  Abstract The temperature dependence of the resistivity of Nb thin films has been studied at T=4.2-300 K. It has been shown that quantum interference between electron-phonon and electron-impurity scattering determines the temperature dependence of the resistivity of the films investigated over a broad temperature range. The magnitude of the contribution of the electron-phonon-impurity,interference is described satisfactorily by the theory developed by Reizer and Sergeev {Zh. Eksp. Teor. Fiz. 92,2291 (1987) [Sov. Phys. JETP 65, 1291 (1987)l). The interaction constants of electrons with longitudinal and transverse phonons in Nb films have been determined for the first time by comparing the experimental data with the theory. The values of the constants obtained are consistent with the data on the inelastic electron-phonon scattering times in the films investigated. The contribution of the transverse phonons is dominant both in the interference correction to the resistivity and in the electron energy relaxation.  
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  Area Expedition Conference  
  Notes Approved no  
  Call Number RPLAB @ phisix @ Serial 989  
Permanent link to this record
 
 
Author Karasik, B. S.; Milostnaya, I. I.; Zorin, M. A.; Elantev, A. I.; Gol'tsman, G. N.; Gershenzon, E. M. url  doi
openurl 
  Title High speed current switching of homogeneous YBaCuO film between superconducting and resistive states Type Journal Article
  Year (up) 1995 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.  
  Volume 5 Issue 2 Pages 3042-3045  
  Keywords YBCO HTS HEB switches  
  Abstract Transitions of thin structured YBaCuO films from superconducting (S) to normal (N) state and back induced by a supercritical current pulse has been studied. A subnanosecond stage in the film resistance dynamic has been observed. A more gradual (nanosecond) ramp in the time dependence of the resistance follows the fast stage. The fraction of the film resistance which is attained during the fast S-N stage rises with the current amplitude. Subnanosecond N-S switching is more pronounced for smaller amplitudes of driving current and for shorter pulses. The phenomena observed are viewed within the framework of an electron heating model. The expected switching time and repetition rate of an optimized current controlling device are estimated to be 1-2 ps and 80 GHz respectively.  
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  Corporate Author Thesis  
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  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1051-8223 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1620  
Permanent link to this record
 
 
Author Karasik, B. S.; Gol'tsman, G. N.; Voronov, B. M.; Svechnikov, S. I.; Gershenzon, E. M.; Ekstrom, H.; Jacobsson, S.; Kollberg, E.; Yngvesson, K. S. url  doi
openurl 
  Title Hot electron quasioptical NbN superconducting mixer Type Journal Article
  Year (up) 1995 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.  
  Volume 5 Issue 2 Pages 2232-2235  
  Keywords NbN HEB mixers  
  Abstract Hot electron superconductor mixer devices made of thin NbN films on SiO/sub 2/-Si/sub 3/N/sub 4/-Si membrane have been fabricated for 300-350 GHz operation. The device consists of 5-10 parallel strips each 5 /spl mu/m long by 1 /spl mu/m wide which are coupled to a tapered slot-line antenna. The I-V characteristics and position of optimum bias point were studied in the temperature range 4.5-8 K. The performance of the mixer at higher temperatures is closer to that predicted by theory for uniform electron heating. The intermediate frequency bandwidth versus bias has also been investigated. At the operating temperature 4.2 K a bandwidth as wide as 0.8 GHz has been measured for a mixer made of 6 nm thick film. The bandwidth tends to increase with operating temperature. The performance of the NbN mixer is expected to be better for higher frequencies where the absorption of radiation should be more uniform.  
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  Corporate Author Thesis  
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  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1051-8223 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1622  
Permanent link to this record
 
 
Author Karasik, B. S.; Zorin, M. A.; Milostnaya, I. I.; Elantev, A. I.; Gol’tsman, G. N.; Gershenzon, E. M. url  doi
openurl 
  Title Subnanosecond switching of YBaCuO films between superconducting and normal states induced by current pulse Type Journal Article
  Year (up) 1995 Publication J. Appl. Phys. Abbreviated Journal J. Appl. Phys.  
  Volume 77 Issue 8 Pages 4064-4070  
  Keywords YBCO HTS switches  
  Abstract A study is reported of the current switching in high‐quality YBaCuO films deposited onto NdGaO3 and ZrO2 substrates between superconducting (S) and normal (N) states. The films 60–120 nm thick prepared by laser ablation were structured into single strips between gold contacts. The time dependence of the resistance after application of the voltage step to the film was monitored. Experiment performed within certain ranges of voltage amplitudes and temperatures has shown the occurrence of the fast stage (shorter than 400 ps) both in S‐N and N‐S transitions. A fraction of the film resistance changing within this stage in the S‐N transition increases with the current amplitude. A subnanosecond N‐S stage becomes more pronounced for shorter pulses. The fast switching is followed by the much slower change of resistance. The mechanism of switching is discussed in terms of the hot‐electron phenomena in YBaCuO. The contributions of other thermal processes (e.g., a phonon escape from the film, a heat diffusion in the film and substrate, a resistive domain formation) in the subsequent stage of the resistance dynamic have been also discussed. The basic limiting characteristics (average dissipated power, energy needed for switching, maximum repetition rate) of a picosecond switch which is proposed to be developed are estimated.  
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  Corporate Author Thesis  
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  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0021-8979 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1623  
Permanent link to this record
 
 
Author Verevkin, A. I.; Ptitsina, N. G.; Chulkova, G. M.; Gol'tsman, G. N.; Gershenzon, E. M.; Yngvesson, K. S. url  openurl
  Title Electron energy relaxation in a 2D channel in AlGaAs-GaAs heterostructures under quasiequilibrium conditions at low temperatures Type Journal Article
  Year (up) 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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  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1624  
Permanent link to this record
 
 
Author Gol'tsman, G. N.; Karasik, B. S.; Svechnikov, S. I.; Gershenzon, E. M.; Ekström, H.; Kollberg E. url  openurl
  Title Noise temperature of NbN hot—electron quasioptical superconducting mixer in 200-700 GHz range Type Abstract
  Year (up) 1995 Publication Proc. 6th Int. Symp. Space Terahertz Technol. Abbreviated Journal Proc. 6th Int. Symp. Space Terahertz Technol.  
  Volume Issue Pages 268  
  Keywords NbN HEB mixers, noise temperature  
  Abstract The electron heating effect in superconducting films is becoming very attractive for the development of THz range mixers because of the absence of frequency limitations inherent in the bolometric mechanism. However, the evidence for the spectral dependence of the position of optimal operating point has been found recently for NbN thin film devices 1.2 • The effect is presumably attributed to the variation in the absorption of radiation depending on the frequency. Since the resistive state is not spatially uniform the coupling efficiency of the mixer device with radiation can be different for frequencies larger than Zeilh and those smaller than 2Alh (d is the effective superconducting gap in the resistive state). To study the effect more thoroughly we have investigated the noise temperature of quasioptical NbN mixer device with broken hue tapered slot antenna in the frequency range 200-700 GHz. The device consists of several (5-10) parallel strips 1 jim wide and 6-7 tun thick made from NbN film on Si0 2 -Si 3 N 4 -Si membrane. The strips are connected with the gold contacts of the slot-line antenna which serves both as bias and IF leads. We used backward wave oscillators as LO sources and a standard hot/cold load technique for noise temperature measurements. The frequency dependence of noise temperature is mainly determined by two factors: frequency properties of the antenna and frequency dependence of the NbN film impedance. To separate both factors we monitored the frequency dependence of the device responsivity in the detector mode at a higher temperature within the superconducting transition where the impedance of NbN film is close to its normal resistance. In this case the impedance of the device itself is frequency independent. The experimental results will be reported at the Symposium. 1. G. Gollsman, S. Jacobsson, H. EkstrOm, B. Karasik, E. Kollberg, and E. Gershenzon, “Slot-line tapered antenna with NbN hot electron mixer for 300-360 GHz operation,” Proc of the 5th Int. Symp. on Space Terahertz Technology, pp. 209-213a, May 10-12,1994. 2. B.S. Karasik, G.N. Gol i tsman, B.M. Voronov, S.I. Svechnikov, E.M. Gershenzon, H. Ekstrom, S. Jacobsson, E. Kollberg, and K.S. Yngvesson, “Hot electron quasioptical NbN superconducting mixer,” presented at the ASC94, submitted to IEEE Trans. on Appl. Superconductivity.  
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  Series Editor Series Title Abbreviated Series Title  
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  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1627  
Permanent link to this record
 
 
Author Gerecht, E.; Musante, C. F.; Schuch, R.; Lutz, C. R.; Jr.; Yngvesson, K. S.; Mueller, E. R.; Waldivian, J.; Gol'tsman, G. N.; Voronov, B. M.; Gershenzon, E. M. url  openurl
  Title Hot electron detection and mixing experiments in NbN at 119 micrometer wavelength Type Conference Article
  Year (up) 1995 Publication Proc. 6th Int. Symp. Space Terahertz Technol. Abbreviated Journal Proc. 6th Int. Symp. Space Terahertz Technol.  
  Volume Issue Pages 284-293  
  Keywords NbN HEB mixers, detectors  
  Abstract We have performed preliminary experiments with the goal of demonstrating a Hot Electron Bolometric (HEB) mixer for a 119 micrometer wavelength (2.5 THz). We have chosen a NbN device of size 700 x 350 micrometers. This device can easily be coupled to a laser LO source, which is advantageous for performing a prototype experiment. The relatively large size of the device means that the LO power required is in the mW range; this power can be easily obtained from a THz laser source. We have measured the amount of laser power actually absorbed in the device, and from this have estimated the best optical coupling loss to be about 10 di . We are developing methods for improving the optical coupling further. Preliminary measurements of the response of the device to a chopped black-body have not yet resulted in a measured receiver noise temperature. We expect to be able to complete this measurement in the near future.  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 1629  
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