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Gershenzon EM, Gershenzon ME, Goltsman GN, Lulkin A, Semenov AD, Sergeev AV. Electron-phonon interaction in ultrathin Nb films. Sov Phys JETP. 1990;70(3):505–11.
Abstract: A study was made of the heating of electrons in normal resistive states of superconducting thin Nb films. The directly determined relaxation time of the resistance of a sample and the rise of the electron temperature were used to find the electron-phonon interaction time rep,, The dependence of rep, on the mean free path of electrons re,, a 1-'demonstrated, in agreement with the theoretical predictions, that the contribution of the inelastic scattering of electrons by impurities to the energy relaxation process decreased at low temperatures and the observed temperature dependence rep, a T 2 was due to a modification of the phonon spectrum in thin fllms.
1. Much new information on the electron-phonon interaction time?;,, in thin films of normal metals and superconductors has been published recently. This information has been obtained mainly as a result of two types of measurement. One includes experiments on weak electron localization investigated by the method of quantum interference corrections to the conductivity of disordered conductors, which can be used to find the relaxation time T, of the phase of the electron wave function. In the absence of the scattering of electrons by paramagnetic impurities the relaxation time T, is associated with the most effective process of energy relaxation: T;= TL+ rep;, where T,, is the electronelectron relaxation time. At low temperatures, when the dependence T; a T is exhibited by thin disordered films, the dominant channel is that of the electron-electron relaxation and there is a lower limit to the temperature range in which rep, can be investigated.
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Kaganov ML, Lifshitz IM, Tanatarov LV. Relaxation between electrons and the crystalline lattice. Sov Phys JETP. 1957;4(2):173–8.
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Gershenzon EM, Gol'tsman GN, Multanovskii VV, Ptitsina NG. Kinetics of electron and hole binding into excitons in germanium. Sov Phys JETP. 1983;57(2):369–76.
Abstract: The kinetics of binding of free carriers'into excitons under stationary and nonstationary conditions is studied by investigating the submillimeter photoconductivity of Ge in a wide range of temperatures and of excitation levels. It is shown that the absolute values and the temperature dependence of the binding cross section (o- T-'.' ) can be satisfactorily described by the cascade recombination theory. The value of o and its temperature dependence differ significantly from the cross sections, measured in the same manner, for capture by attracting small impurities. Under nonstationary conditions, just as in the case of recombination with shallow impurities, a signifi- cant role is played by the sticking of the carriers in highly excited states.
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Tuchak AN, Gol’tsman GN, Kitaeva GK, Penin AN, Seliverstov SV, Finkel MI, et al. Generation of nanosecond terahertz pulses by the optical rectification method. JETP Lett. 2012;96(2):94–7.
Abstract: The possibility of the generation of quasi-cw terahertz radiation by the optical rectification method for broad-band Fourier unlimited nanosecond laser pulses has been experimentally demonstrated. The broadband radiation of a LiF dye-center laser is used as a pump source of a nonlinear optical oscillator. The energy efficiency of terahertz optical frequency conversion in a periodically polarized lithium niobate crystal is 4 × 10−9 at a pump power density of 7 MW/cm2.
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Baeva EM, Titova NA, Kardakova AI, Piatrusha SU, Khrapai VS. Universal bottleneck for thermal relaxation in disordered metallic films. Jetp Lett. 2020;111(2):104–8.
Abstract: We study the heat relaxation in current biased metallic films in the regime of strong electron–phonon coupling. A thermal gradient in the direction normal to the film is predicted, with a spatial temperature profile determined by the temperature-dependent heat conduction. In the case of strong phonon scattering, the heat conduction occurs predominantly via the electronic system and the profile is parabolic. This regime leads to the linear dependence of the noise temperature as a function of bias voltage, in spite of the fact that all the dimensions of the film are large compared to the electron–phonon relaxation length. This is in stark contrast to the conventional scenario of relaxation limited by the electron–phonon scattering rate. A preliminary experimental study of a 200-nm-thick NbN film indicates the relevance of our model for materials used in superconducting nanowire single-photon detectors.
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Gol’tsman GN, Smirnov KV. Electron-phonon interaction in a two-dimensional electron gas of semiconductor heterostructures at low temperatures. Jetp Lett. 2001;74(9):474–9.
Abstract: Theoretical and experimental works devoted to studying electron-phonon interaction in the two-dimensional electron gas of semiconductor heterostructures at low temperatures in the case of strong heating in an electric field under quasi-equilibrium conditions and in a quantizing magnetic field perpendicular to the 2D layer are considered.
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Smirnov KV, Ptitsina NG, Vakhtomin YB, Verevkin AA, Gol’tsman GN, Gershenzon EM. Energy relaxation of two-dimensional electrons in the quantum Hall effect regime. JETP Lett. 2000;71(1):31–4.
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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Verevkin AA, Ptitsina NG, Smirnov KV, Gol’tsman GN, Gershenzon EM, Ingvesson KS. Direct measurements of energy relaxation times on an AlGaAs/GaAs heterointerface in the range 4.2–50 K. JETP Lett. 1996;64(5):404–9.
Abstract: The temperature dependence of the energy relaxation time τe (T) of a two-dimensional electron gas at an AlGaAs/GaAs heterointerface is measured under quasiequilibrium conditions in the region of the transition from scattering by acoustic phonons to scattering with the participation of optical phonons. The temperature interval of constant τe, where scattering by the deformation potential predominates, is determined. In the preceding, low-temperature region, where piezoacoustic and deformation-potential-induced scattering processes coexist, τ e decreases slowly with increasing temperature. Optical phonons start to participate in the scattering processes at T∼25 K (the characteristic phonon lifetime was equal to τLOτ4.5 ps). The energy losses calculated from the τe data in a model with an effective nonequilibrium electron temperature agree with the published data obtained under strong heating conditions.
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Verevkin AI, Ptitsina NG, Chulkova GM, Gol'tsman GN, Gershenzon EM, Yngvesson KS. Electron energy relaxation in a 2D channel in AlGaAs-GaAs heterostructures under quasiequilibrium conditions at low temperatures. JETP Lett. 1995;61(7):591–5.
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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Aksaev EE, Gershenzon EM, Gol'tsman GN, Semenov AD, Sergeev AV. Interaction of electrons with thermal phonons in YBa2Cu3O7-δ films at low temperatures. JETP Lett. 1989;50(5):283–6.
Abstract: The time of electron-phonon interaction tau(eph) in YBaCuO films at low temperatures is studied. This is measured as the time of resistance relaxation in the resistive state of the superconducter, and is also determined from the increase in resistance under the action of radiation. Consistent results of these methods show that resistance relaxation in the resistive state is caused by cooling of the electron subsystem with respect to the phonon subsystem. The time tau(eph) is found to be inversely proportional to the temperature and comes to 80 ps when T = 1.6 K and 5 ps when T = 30 K. 6 refs.
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