Sidorova, M. V., Kozorezov, A. G., Semenov, A. V., Korneeva, Y. P., Mikhailov, M. Y., Devizenko, A. Y., et al. (2018). Nonbolometric bottleneck in electron-phonon relaxation in ultrathin WSi films. Phys. Rev. B, 97(18), 184512 (1 to 13).
Abstract: We developed the model of the internal phonon bottleneck to describe the energy exchange between the acoustically soft ultrathin metal film and acoustically rigid substrate. Discriminating phonons in the film into two groups, escaping and nonescaping, we show that electrons and nonescaping phonons may form a unified subsystem, which is cooled down only due to interactions with escaping phonons, either due to direct phonon conversion or indirect sequential interaction with an electronic system. Using an amplitude-modulated absorption of the sub-THz radiation technique, we studied electron-phonon relaxation in ultrathin disordered films of tungsten silicide. We found an experimental proof of the internal phonon bottleneck. The experiment and simulation based on the proposed model agree well, resulting in τe−ph∼140–190 ps at TC=3.4K, supporting the results of earlier measurements by independent techniques.
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Varyukhin, S. V., Zakharov, A. A., Gershenzon, E. M., Gol'tsman, G. N., Ptitsyna, N. G., & Chulkova, G. M. (1990). AC losses and submillimeter absorption in single crystals La2CuO4. Phys. B Condens. Mat., 165-166, 1269–1270.
Abstract: The La2CuO4 single crystals were used to carry out the measurements of transmission spectra within the submillimeter range of wavelengths, as well as the capacitance C and conductivity G in the region of acoustic frequencies of the metal-dielectric-La2Cu04 system at low temperatures. The optical spectra display a threshold character. There takes place a sharp decreasing of transmission signal in the energy range of hυ>1.5meV. The C(ω,T) and G(ω,T) dependences have a universal form characteristic of relaxation processes of the Debye type. The relaxation time dependence displays a thermoactivation character τ(T)-exp(ξ/T) with a gap value of ξ≃2meV,coinciding with the optical one. It is assumed that there exist excitations with a characteristic energy ~ 2meV in La2Cu04.A possible nature of the revealed low-energy excitations is discussed.
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Sergeev, A., Karasik, B. S., Ptitsina, N. G., Chulkova, G. M., Il'in, K. S., & Gershenzon, E. M. (1999). Electron–phonon interaction in disordered conductors. Phys. Rev. B Condens. Matter, 263-264, 190–192.
Abstract: The electron–phonon interaction is strongly modified in conductors with a small value of the electron mean free path (impure metals, thin films). As a result, the temperature dependencies of both the inelastic electron scattering rate and resistivity differ significantly from those for pure bulk materials. Recent complex measurements have shown that modified dependencies are well described at K by the electron interaction with transverse phonons. At helium temperatures, available data are conflicting, and cannot be described by an universal model.
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Verevkin, A., Gershenzon, E. M., Gol'tsman, G. N., Ptitsina, N. G., Chulkova, G. M., Smirnov, K. S., et al. (2002). Direct measurements of energy relaxation times in two-dimensional structures under quasi-equilibrium conditions. In Mater. Sci. Forum (Vol. 384-3, pp. 107–116).
Abstract: A new microwave technique was successfully applied for direct studies of energy relaxation times in two-dimensional AlGaAs/GaAs structures under quasi-equilibrium conditions in the nanosecond and picosecond time scale. We report our results of energy relaxation time measurements in the temperature range 1.6-50 K, in quantum Hall effect regime in magnetic fields up to 4 T.
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