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Author Verevkin, A. A.; Ptitsina, N. G.; Smirnov, K. V.; Gol’tsman, G. N.; Gershenzon, E. M.; Ingvesson, K. S.
Title Direct measurements of energy relaxation times on an AlGaAs/GaAs heterointerface in the range 4.2–50 K Type Journal Article
Year 1996 Publication JETP Lett. Abbreviated Journal JETP Lett.
Volume 64 Issue 5 Pages 404-409
Keywords 2DEG, AlGaAs/GaAs heterostructures
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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ISSN 0021-3640 ISBN Medium
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Notes http://jetpletters.ru/ps/981/article_14955.shtml (“Прямые измерения времен энергетической релаксации на гетерогранице AlGaAs/GaAs в диапазоне 4.2 – 50 К”) Approved no
Call Number Serial (up) 1608
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Author Verevkin, A. I.; Ptitsina, N. G.; Chulkova, G. M.; Gol'tsman, G. N.; Gershenzon, E. M.; Yngvesson, K. S.
Title Electron energy relaxation in a 2D channel in AlGaAs-GaAs heterostructures under quasiequilibrium conditions at low temperatures Type Journal Article
Year 1995 Publication JETP Lett. Abbreviated Journal JETP Lett.
Volume 61 Issue 7 Pages 591-595
Keywords 2DEG, AlGaAs/GaAs heterostructures
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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Notes Approved no
Call Number Serial (up) 1624
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Author Aksaev, E. E.; Gershenzon, E. M.; Gol'tsman, G. N.; Semenov, A. D.; Sergeev, A. V.
Title Interaction of electrons with thermal phonons in YBa2Cu3O7-δ films at low temperatures Type Journal Article
Year 1989 Publication JETP Lett. Abbreviated Journal JETP Lett.
Volume 50 Issue 5 Pages 283-286
Keywords YBCO HTS films
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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Notes Approved no
Call Number Serial (up) 1690
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Author Gershenzon, E. M.; Gol'tsman, G. N.; Karasik, B. S.; Semenov, A. D.
Title Measurement of the energy gap in the compound YBaCu3O9-δ on the basis of the IR absorption spectrum Type Journal Article
Year 1987 Publication JETP Lett. Abbreviated Journal JETP Lett.
Volume 46 Issue 5 Pages 237-238
Keywords YBCO HTS detectors
Abstract For the first time the long-wave infrared absorption spectrum has been measured by means of the bolometric effect and energy gap for high-temperature superconducting ceramics YBa/sub 2/Cu/sub 3/O/sub 9-delta/ has been determined from absorption threshold. 2delta/kT/sub c/ value is equal to 0.6.
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Notes Approved no
Call Number Serial (up) 1703
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Author Gol'tsman, G. N.; Gusinskii, E. N.; Malyavkin, A. V.; Ptitsina, N. G.; Selevko, A. G.; Edel'shtein, V. M.
Title The excitonic Zeeman effect in uniaxially-strained germanium Type Journal Article
Year 1987 Publication Sov. Phys. JETP Abbreviated Journal Sov. Phys. JETP
Volume 65 Issue 6 Pages 1233-1241
Keywords Ge, Zeeman effect
Abstract We have carried out a high-resolution spectroscopic study of the absorption of submillimeter radiation by free excitons in germanium compressed along the [ 1 11 ] axis in a magnetic field parallel to the compression axis. In particular, we studied the splitting of the 1s- 2p transition in fields up to 6 kOe at T = 1.6 K, and observed a complex pattern in the Zeeman splitting which we believe is related to the effect of thermal motion of the excitons in a magnetic field on their internal structure (the magneto-Stark effect). The calculated submillimeter spectrum of excitons agrees with the experimental data. We predict that in a magnetic field the energy of the 2p, term is a minimum at a finite value of the exciton momentum perpendicular to the field-that is, the energy minimum forms a ring in momentum space. It follows that the density of states for this term must be a nonmonotonic function of the energy. A theory is developed of analogous phenomena in positronium.
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Notes Approved no
Call Number Serial (up) 1705
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