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Author |
Chulcova, G. M.; Ptitsina, N. G.; Gershenzon, E. M.; Gershenzon, M. E.; Sergeev, A. V. |
Title |
Effect of the interference between electron-phonon and electron-impurity (boundary) scattering on resistivity Nb, Al, Be films |
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Conference Article |
Year |
1996 |
Publication |
Czech J. Phys. |
Abbreviated Journal |
Czech J. Phys. |
Volume |
46 |
Issue |
S5 |
Pages |
2489-2490 |
Keywords |
Al, Be, Nb films |
Abstract |
The temperature dependence of the resistivity of thin Nb, Al, Be films has been studied over a wide temperature range 4-300 K. We have found that the temperature-dependent correction to the residual resistivity is well described by the sum of the Bloch-Grüneisen term and the term originating from the interference between electron-phonon and electron-impurity scattering. Study of the transport interference phenomena allows to determine electron-phonon coupling in disordered metals. The interference term is proportional to T2 and also to the residual resistivity and dominates over the Bloch-Grüneisen term at low temperatures (T<40 K). |
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0011-4626 |
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1767 |
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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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1383 |
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Author |
Gershenzon, E. M.; Gol'tsman, G. N.; Kagane, M. L. |
Title |
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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1727 |
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Author |
Gershenzon, E. M.; Gol'tsman, G. N.; Elant'ev, A. I. |
Title |
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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1728 |
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Шангина, Е. Л.; Смирнов, К. В.; Морозов, Д. В.; Ковалюк, В. В.; Гольцман, Г. Н.; Веревкин, А. А.; Торопов, А. И. |
Title |
Полоса и потери преобразования полупроводникового смесителя с фононным каналом охлаждения двумерных электронов |
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Journal Article |
Year |
2010 |
Publication |
Физика и техника полупроводников |
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44 |
Issue |
11 |
Pages |
1475-1478 |
Keywords |
2DEG, AlGaAs/GaAs heterostructures mixers |
Abstract |
Методом субмиллиметровой спектроскопии с высоким временным разрешением измерены температурная и концентрационная зависимости полосы преобразования смесителей терагерцового диапазона AlGaAs/GaAs на разогреве двумерных электронов с фононным каналом их охлаждения. Полоса преобразования на уровне 3 дБ (f3 dB) при 4.2 K при изменении концентрации ns варьируется в пределах 150-250 МГц в соответствии со степенным законом f3 dB propto ns-0.5, что соответствует доминирующему механизму рассеяния на пьезоэлектрических фононах. Минимальное значение коэффициента потерь преобразования полупроводникового смесителя достигается в структурах с высокой подвижностью носителей mu>3·105 см2/В·с при 4.2 K. |
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Duplicated as 1216 |
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RPLAB @ gujma @ |
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702 |
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