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Author Verevkin, A. A.; Ptitsina, N. G.; Chulcova, G. M.; Gol'Tsman, G. N.; Gershenzon, E. M.; Yngvesson, K. S. url  doi
openurl 
  Title Determination of the limiting mobility of a two-dimensional electron gas in AlxGa1-xAs/GaAs heterostructures and direct measurement of the energy relaxation time Type Journal Article
  Year 1996 Publication Phys. Rev. B Condens. Matter. Abbreviated Journal Phys. Rev. B Condens. Matter.  
  Volume 53 Issue 12 Pages R7592-R7595  
  Keywords 2DEG, AlGaAs/GaAs heterostructures  
  Abstract We present results for a method to measure directly the energy relaxation time (τe) for electrons in a single AlxGa1−xAs/GaAs heterojunction; measurements were performed from 1.6 to 15 K under quasiequilibrium conditions. We find τeαT−1 below 4 K, and τe independent of T above 4 K. We have also measured the energy-loss rate, ⟨Q⟩, by the Shubnikov-de Haas technique, and find ⟨Q⟩α(T3e−T3) for T<~4.2 K; Te is the electron temperature. The values and temperature dependence of τe and ⟨Q⟩ for T<4 K agree with calculations based on piezoelectric and deformation potential acoustic phonon scattering. At 4.2 K, we can also estimate the momentum relaxation time, τm, from our measured τe. This leads to a preliminary estimate of the phonon-limited mobility at 4.2 K of μ=3×107 cm2/Vs (ns=4.2×1011 cm−2), which agrees well with published numerical calculations, as well as with an earlier indirect estimate based on measurements on a sample with much higher mobility.  
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  Series Volume Series Issue Edition  
  ISSN 0163-1829 ISBN Medium  
  Area Expedition Conference  
  Notes (down) PMID:9982274 Approved no  
  Call Number Serial 1612  
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Author Gorokhov, G.; Bychanok, D.; Gayduchenko, I.; Rogov, Y.; Zhukova, E.; Zhukov, S.; Kadyrov, L.; Fedorov, G.; Ivanov, E.; Kotsilkova, R.; Macutkevic, J.; Kuzhir, P. url  doi
openurl 
  Title THz spectroscopy as a versatile tool for filler distribution diagnostics in polymer nanocomposites Type Journal Article
  Year 2020 Publication Polymers (Basel) Abbreviated Journal Polymers (Basel)  
  Volume 12 Issue 12 Pages 3037 (1 to 14)  
  Keywords THz spectroscopy; nanocomposites, percolation threshold, time-domain spectroscopy, time-domain spectrometer, TDS  
  Abstract Polymer composites containing nanocarbon fillers are under intensive investigation worldwide due to their remarkable electromagnetic properties distinguished not only by components as such, but the distribution and interaction of the fillers inside the polymer matrix. The theory herein reveals that a particular effect connected with the homogeneity of a composite manifests itself in the terahertz range. Transmission time-domain terahertz spectroscopy was applied to the investigation of nanocomposites obtained by co-extrusion of PLA polymer with additions of graphene nanoplatelets and multi-walled carbon nanotubes. The THz peak of permittivity's imaginary part predicted by the applied model was experimentally shown for GNP-containing composites both below and above the percolation threshold. The physical nature of the peak was explained by the impact on filler particles excluded from the percolation network due to the peculiarities of filler distribution. Terahertz spectroscopy as a versatile instrument of filler distribution diagnostics is discussed.  
  Address Institute of Photonics, University of Eastern Finland, Yliopistokatu 7, FI-80101 Joensuu, Finland  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2073-4360 ISBN Medium  
  Area Expedition Conference  
  Notes (down) PMID:33353036; PMCID:PMC7767186 Approved no  
  Call Number Serial 1780  
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Author Pentin, I.; Vakhtomin, Y.; Seleznev, V.; Smirnov, K. url  doi
openurl 
  Title Hot electron energy relaxation time in vanadium nitride superconducting film structures under THz and IR radiation Type Journal Article
  Year 2020 Publication Sci. Rep. Abbreviated Journal Sci. Rep.  
  Volume 10 Issue 1 Pages 16819  
  Keywords VN HEB  
  Abstract The paper presents the experimental results of studying the dynamics of electron energy relaxation in structures made of thin (d approximately 6 nm) disordered superconducting vanadium nitride (VN) films converted to a resistive state by high-frequency radiation and transport current. Under conditions of quasi-equilibrium superconductivity and temperature range close to critical (~ Tc), a direct measurement of the energy relaxation time of electrons by the beats method arising from two monochromatic sources with close frequencies radiation in sub-THz region (omega approximately 0.140 THz) and sources in the IR region (omega approximately 193 THz) was conducted. The measured time of energy relaxation of electrons in the studied VN structures upon heating of THz and IR radiation completely coincided and amounted to (2.6-2.7) ns. The studied response of VN structures to IR (omega approximately 193 THz) picosecond laser pulses also allowed us to estimate the energy relaxation time in VN structures, which was ~ 2.8 ns and is in good agreement with the result obtained by the mixing method. Also, we present the experimentally measured volt-watt responsivity (S~) within the frequency range omega approximately (0.3-6) THz VN HEB detector. The estimated values of noise equivalent power (NEP) for VN HEB and its minimum energy level (deltaE) reached NEP@1MHz approximately 6.3 x 10(-14) W/ radicalHz and deltaE approximately 8.1 x 10(-18) J, respectively.  
  Address National Research University Higher School of Economics, 20 Myasnitskaya Str., Moscow, 101000, Russia  
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  Series Volume Series Issue Edition  
  ISSN 2045-2322 ISBN Medium  
  Area Expedition Conference  
  Notes (down) PMID:33033360; PMCID:PMC7546726 Approved no  
  Call Number Serial 1797  
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Author Matyushkin, Y.; Danilov, S.; Moskotin, M.; Belosevich, V.; Kaurova, N.; Rybin, M.; Obraztsova, E. D.; Fedorov, G.; Gorbenko, I.; Kachorovskii, V.; Ganichev, S. url  doi
openurl 
  Title Helicity-sensitive plasmonic terahertz interferometer Type Journal Article
  Year 2020 Publication Nano Lett. Abbreviated Journal Nano Lett.  
  Volume 20 Issue 10 Pages 7296-7303  
  Keywords graphene, plasmonic interferometer, radiation helicity, terahertz radiation  
  Abstract Plasmonic interferometry is a rapidly growing area of research with a huge potential for applications in the terahertz frequency range. In this Letter, we explore a plasmonic interferometer based on graphene field effect transistor connected to specially designed antennas. As a key result, we observe helicity- and phase-sensitive conversion of circularly polarized radiation into dc photovoltage caused by the plasmon-interference mechanism: two plasma waves, excited at the source and drain part of the transistor, interfere inside the channel. The helicity-sensitive phase shift between these waves is achieved by using an asymmetric antenna configuration. The dc signal changes sign with inversion of the helicity. A suggested plasmonic interferometer is capable of measuring the phase difference between two arbitrary phase-shifted optical signals. The observed effect opens a wide avenue for phase-sensitive probing of plasma wave excitations in two-dimensional materials.  
  Address CENTERA Laboratories, Institute of High Pressure Physics, PAS, 01-142 Warsaw, Poland  
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  Series Volume Series Issue Edition  
  ISSN 1530-6984 ISBN Medium  
  Area Expedition Conference  
  Notes (down) PMID:32903004 Approved no  
  Call Number Serial 1781  
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Author Kitaeva, G. K.; Kornienko, V. V.; Kuznetsov, K. A.; Pentin, I. V.; Smirnov, K. V.; Vakhtomin, Y. B. url  doi
openurl 
  Title Direct detection of the idler THz radiation generated by spontaneous parametric down-conversion Type Journal Article
  Year 2019 Publication Opt. Lett. Abbreviated Journal Opt. Lett.  
  Volume 44 Issue 5 Pages 1198-1201  
  Keywords HEB applications  
  Abstract We study parametric down-conversion (PDC) of optical laser radiation in the strongly frequency non-degenerate regime which is promising for the generation of quantum-correlated pairs of extremely different spectral ranges, the optical and the terahertz (THz) ones. The possibility to detect tenuous THz-frequency photon fluxes generated under low-gain spontaneous PDC is demonstrated using a hot electron bolometer. Then experimental dependences of the THz radiation power on the detection angle and on the pump intensity are analyzed.  
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  ISSN 0146-9592 ISBN Medium  
  Area Expedition Conference  
  Notes (down) PMID:30821747 Approved no  
  Call Number Serial 1801  
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