| Records |
| Author |
Gousev, Y. P.; Semenov, A. D.; Gol'tsman, G. N.; Sergeev, A. V.; Gershenzon, E. M. |
Title  |
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 |
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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 |
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1649 |
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| Author |
Beck, Matthias; Leiderer, Paul; Kabanov, Viktor V.; Gol'tsman, Gregory; Helm, Manfred; Demsar, Jure |
| Title |
Energy-gap dynamics of a superconductor NbN studied by time-resolved terahertz spectroscopy |
Type |
Abstract |
| Year |
2012 |
Publication |
INIS |
Abbreviated Journal |
INIS |
| Volume |
45 |
Issue |
12 |
Pages |
1-3 |
| Keywords |
NbN energy gap |
| Abstract |
Using time-resolved terahertz (THz) spectroscopy we performed direct studies of the photoinduced suppression and recovery of the SC gap in a conventional SC 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 important microscopic constants: the Cooper pair-breaking rate via phonon absorption and the bare quasiparticle recombination rate. From the latter we were able to extract the dimensionless electron-phonon coupling constant, λ=1.1±0.1, in excellent agreement with theoretical estimates. The technique also allowed us to determine the absorbed energy required to suppress SC, which in NbN equals the thermodynamic condensation energy (in cuprates the two differ by an order of magnitude). Finally, we present the first studies of dynamics following resonant excitation with intense narrow band THz pulses tuned to above and below the superconducting gap. These suggest an additional process, particularly pronounced near Tc, that could be attributed to amplification of SC via effective quasiparticle cooling. |
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no |
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1383 |
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| Author |
Beck, M.; Klammer, M.; Lang, S.; Leiderer, P.; Kabanov, V. V.; Gol'tsman, G. N.; Demsar, J. |
| Title |
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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RPLAB @ gujma @ |
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641 |
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Beck, M.; Klammer, M.; Lang, S.; Leiderer, P.; Kabanov, V. V.; Gol’tsman, G. N.; Demsar, J. |
| Title |
Energy-gap dynamics of superconducting NbN thin films studied by time-resolved terahertz spectroscopy |
Type |
Miscellaneous |
| Year |
2011 |
Publication |
arXiv |
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Issue |
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Pages |
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| 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, \lambda = 1.1 +/- 0.1, which is in excellent agreement with theoretical estimates. |
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Duplicated as 641 |
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no |
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1388 |
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| Author |
Casaburi, A.; Ejrnaes, M.; Quaranta, O.; Gaggero, A.; Mattioli, F.; Leoni, R.; Voronov, B.; Gol'tsman, G.; Lisitskiy, M.; Esposito, E.; Nappi, C.; Cristiano, R.; Pagano, S. |
| Title |
Experimental characterization of NbN nanowire optical detectors with parallel stripline configuration |
Type |
Conference Article |
| Year |
2008 |
Publication |
J. Phys.: Conf. Ser. |
Abbreviated Journal |
J. Phys.: Conf. Ser. |
| Volume |
97 |
Issue |
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Pages |
012265 (1 to 6) |
| Keywords |
NbN SSPD, SNSPD |
| Abstract |
We have developed a novel geometrical configuration for NbN-based superconducting single photon optical detector (SSPD) that achieves two goals: a much lower intrinsic impedance, and a consequently greater bandwidth, and a much larger signal amplitude compared to the standard meandered configuration. This has been obtained by implementing a properly designed parallel stripline structure where a cascade switching mechanism occurs when one of the striplines is hit by an optical photon. The overall switching occurs synchronously and in a very short time, giving rise to a strong and fast voltage pulse. The SSPD have been realized using state of the art NbN deposition technology and e-beam lithography. The strips are 100 nm wide and 5 μm long and have been realized with 4 nm NbN film on sapphire and Si substrate. We report on experimental characterization of such novel devices. The performances of the proposed novel type of SSPD are compared with standard SSPD design and results in terms of signal amplitude, risetime and effective detection area. |
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IOP Publishing |
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| ISSN |
1742-6596 |
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8th European Conference on Applied Superconductivity (EUCAS 2007) |
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1416 |
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