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Author Yang, Y.; Fedorov, G.; Shafranjuk, S. E.; Klapwijk, T. M.; Cooper, B. K.; Lewis, R. M.; Lobb, C. J.; Barbara, P. url  doi
openurl 
  Title Electronic transport and possible superconductivity at Van Hove singularities in carbon nanotubes Type Journal Article
  Year 2015 Publication Nano Lett. Abbreviated Journal Nano Lett.  
  Volume 15 Issue 12 Pages (down) 7859-7866  
  Keywords carbon nanotubes, CNT, tunable superconductivity, van Hove singularities  
  Abstract Van Hove singularities (VHSs) are a hallmark of reduced dimensionality, leading to a divergent density of states in one and two dimensions and predictions of new electronic properties when the Fermi energy is close to these divergences. In carbon nanotubes, VHSs mark the onset of new subbands. They are elusive in standard electronic transport characterization measurements because they do not typically appear as notable features and therefore their effect on the nanotube conductance is largely unexplored. Here we report conductance measurements of carbon nanotubes where VHSs are clearly revealed by interference patterns of the electronic wave functions, showing both a sharp increase of quantum capacitance, and a sharp reduction of energy level spacing, consistent with an upsurge of density of states. At VHSs, we also measure an anomalous increase of conductance below a temperature of about 30 K. We argue that this transport feature is consistent with the formation of Cooper pairs in the nanotube.  
  Address Department of Physics, Georgetown University , Washington, District of Columbia 20057, United States  
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  Series Volume Series Issue Edition  
  ISSN 1530-6984 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:26506109; Suuplementary info (attached to pdf) DOI: 10.1021/acs.nanolett.5b02564 Approved no  
  Call Number Serial 1782  
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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 (down) 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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  ISSN 0163-1829 ISBN Medium  
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  Notes PMID:9982274 Approved no  
  Call Number Serial 1612  
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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 (down) 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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  ISSN 1530-6984 ISBN Medium  
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  Notes PMID:32903004 Approved no  
  Call Number Serial 1781  
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Author Vetter, A.; Ferrari, S.; Rath, P.; Alaee, R.; Kahl, O.; Kovalyuk, V.; Diewald, S.; Goltsman, G. N.; Korneev, A.; Rockstuhl, C.; Pernice, W. H. P. url  doi
openurl 
  Title Cavity-enhanced and ultrafast superconducting single-photon detectors Type Journal Article
  Year 2016 Publication Nano Lett. Abbreviated Journal Nano Lett.  
  Volume 16 Issue 11 Pages (down) 7085-7092  
  Keywords SSPD; SNSPD; multiphoton detection; nanophotonic circuit; photonic crystal cavity  
  Abstract Ultrafast single-photon detectors with high efficiency are of utmost importance for many applications in the context of integrated quantum photonic circuits. Detectors based on superconductor nanowires attached to optical waveguides are particularly appealing for this purpose. However, their speed is limited because the required high absorption efficiency necessitates long nanowires deposited on top of the waveguide. This enhances the kinetic inductance and makes the detectors slow. Here, we solve this problem by aligning the nanowire, contrary to usual choice, perpendicular to the waveguide to realize devices with a length below 1 mum. By integrating the nanowire into a photonic crystal cavity, we recover high absorption efficiency, thus enhancing the detection efficiency by more than an order of magnitude. Our cavity enhanced superconducting nanowire detectors are fully embedded in silicon nanophotonic circuits and efficiently detect single photons at telecom wavelengths. The detectors possess subnanosecond decay ( approximately 120 ps) and recovery times ( approximately 510 ps) and thus show potential for GHz count rates at low timing jitter ( approximately 32 ps). The small absorption volume allows efficient threshold multiphoton detection.  
  Address Institute of Physics, University of Munster , 48149 Munster, Germany  
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  Language English Summary Language Original Title  
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  ISSN 1530-6984 ISBN Medium  
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  Notes PMID:27759401 Approved no  
  Call Number Serial 1208  
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Author Divochiy, A.; Misiaszek, M.; Vakhtomin, Y.; Morozov, P.; Smirnov, K.; Zolotov, P.; Kolenderski, P. url  doi
openurl 
  Title Single photon detection system for visible and infrared spectrum range Type Journal Article
  Year 2018 Publication Opt. Lett. Abbreviated Journal Opt. Lett.  
  Volume 43 Issue 24 Pages (down) 6085-6088  
  Keywords  
  Abstract We demonstrate niobium nitride based superconducting single-photon detectors sensitive in the spectral range 452-2300 nm. The system performance was tested in a real-life experiment with correlated photons generated by means of spontaneous parametric downconversion, where one photon was in the visible range and the other was in the infrared range. We measured a signal to noise ratio as high as 4x10(4) in our detection setting. A photon detection efficiency as high as 64% at 1550 nm and 15% at 2300 nm was observed.  
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  ISSN 0146-9592 ISBN Medium  
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  Notes https://arxiv.org/abs/1807.04273 Approved no  
  Call Number Serial 1227  
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