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Author Nebosis, R. S.; Heusinger, M. A.; Schatz, W.; Renk, K. F.; Gol’tsman, G. N.; Karasik, B. S.; Semenov, A. D.; Gershenzon, E. M.
Title Ultrafast photoresponse of a structured YBa2Cu3O7-δ thin film to ultrashort FIR laser pulses Type Journal Article
Year 1993 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.
Volume 3 Issue (up) 1 Pages 2160-2162
Keywords YBCO HTS detectors
Abstract The authors have investigated the photoinduced voltage response of a current-carrying structured YBa2Cu3O7-δ thin film to ultrashort far-infrared (FIR) laser pulses in the frequency range from 0.7 THz to 7 THz. The detector has shown an almost constant sensitivity of 1 mV/W and a noise equivalent power of less than 5*10/sup -7/ W/ square root Hz. The temperature dependence of the decay time of the detector signal was studied for temperatures around the transition temperature of the film ( approximately 80 K). For a detector temperature where dR/dT had its maximum, the authors observed bolometric signals with decay times of about 2 ns, and for lower temperatures they observed nonbolometric signals with decay times of approximately 120 ps; the duration of the nonbolometric signals was limited by the time resolution of the electronic registration equipment.
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Call Number Serial 1658
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Author Semenov, A. D.; Goghidze, I. G.; Gol’tsman, G. N.; Sergeev, A. V.; Aksaev, E. E.; Gershenzon, E. M.
Title Non-equilibrium quasiparticle response to radiation and bolometric effect in YBaCuO films Type Journal Article
Year 1993 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.
Volume 3 Issue (up) 1 Pages 2132-2135
Keywords YBCO HTS HEB detectors
Abstract The voltage photoresponse of structured current biased YBCO films on different substrates to 20-ps laser pulses of 0.63- mu m and 1.54- mu m wavelengths and to continuously modulated radiation of 2-mm wavelength is measured to temperatures around Tc. Fast picosecond decay of the response to pulsed radiation is followed by slow exponential relaxation with a nanosecond characteristic time depending on the substrate material and film dimensions. The slow component does not depend on wavelength and is attributed to the bolometric effect, while the magnitude of the fast component associated with nonequilibrium response rises with wavelength. More than an order-of-magnitude increase of the nonequilibrium response is seen from near-infrared to millimeter-wave range. This dependence plausibly reflects the low efficiency of multiplication of photoexcited electrons in YBaCuO compared to conventional superconductors.
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ISSN 1558-2515 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1659
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Author Gershenzon, E. M.; Gol'tsman, G. N.; Ptitsina, N. G.
Title Investigation of free excitons in Ge and their condensation at submillimeter wavelengths Type Journal Article
Year 1976 Publication Sov. Phys. JETP Abbreviated Journal Sov. Phys. JETP
Volume 43 Issue (up) 1 Pages 116-122
Keywords Ge, free excitons
Abstract Results are presented of an investigation of free excitons in Ge in the submillimeter wavelength range for low as well as for high excitation levels when interaction between the excitons becomes important. The free-exciton energy spectrum is discussed. It is shown that the drop radii and their concentrations can be determined by measuring the temperature dependence of the free-exciton concentration. A section of the phase diagram is obtained in the 0.5-2.8 K temperature range for the free excitons+condensate system.
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Notes Approved no
Call Number Serial 1731
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Author Mel’nikov, A. P.; Gurvich, Y. A.; Shestakov, L. N.; Gershenzon, E. M.
Title Magnetic field effects on the nonohmic impurity conduction of uncompensated crystalline silicon Type Journal Article
Year 2001 Publication Jetp Lett. Abbreviated Journal Jetp Lett.
Volume 73 Issue (up) 1 Pages 44-47
Keywords uncompensated crystalline silicon, nonohmic impurity conduction, magnetic field
Abstract The impurity conduction of a series of crystalline silicon samples with the concentration of major impurity N ≈ 3 × 1016 cm−3 and with a varied, but very small, compensation K was measured as a function of the electric field E in various magnetic fields H-σ(H, E). It was found that, at K < 10−3 and in moderate E, where these samples are characterized by a negative nonohmicity (dσ(0, E)/dE < 0), the ratio σ(H, E)/σ(0, E) > 1 (negative magnetoresistance). With increasing E, these inequalities are simultaneously reversed (positive nonohmicity and positive magnetoresistance). It is suggested that both negative and positive nonohmicities are due to electron transitions in electric fields from impurity ground states to states in the Mott-Hubbard gap.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-3640 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1752
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Author Gershenzon, E. M.; Gol'tsman, G. N.; Potapov, V. D.; Sergeev, A. V.
Title Restriction of microwave enhancement of superconductivity in impure superconductors due to electron-electron interaction Type Journal Article
Year 1991 Publication Phys. B Condens. Mat. Abbreviated Journal Phys. B Condens. Mat.
Volume 169 Issue (up) 1-4 Pages 629-630
Keywords impure superconductors
Abstract Transition from microwave enhancement of supercurrent to superconductivity suppression is investigated in impure superconductors. It is demonstrated that frequency range of enhancement effect narrows with the decrease of electron mean free path, ℓ, and at ℓ⩽1nm electron heating is observed in the whole frequency range. Dependences of frequency boundaries on ℓ are explained by taking into account strong electron-electron interaction in impure metals.
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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 1682
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