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Author (down) Korneeva, Y. P.; Manova, N. N.; Florya, I. N.; Mikhailov, M. Y.; Dobrovolskiy, O. V.; Korneev, A. A.; Vodolazov, D. Y.
Title Different single-photon response of wide and narrow superconducting MoxSi1−x strips Type Journal Article
Year 2020 Publication Phys. Rev. Applied Abbreviated Journal Phys. Rev. Applied
Volume 13 Issue 2 Pages 024011 (1 to 7)
Keywords MoSi SSPD, SNSPD
Abstract The photon count rate (PCR) of superconducting single-photon detectors made of MoxSi1−x films shaped as a 2-μm-wide strip and a 115-nm-wide meander strip line is studied experimentally as a function of the dc biasing current at different values of the perpendicular magnetic field. For the wide strip, a crossover current Icross is observed, below which the PCR increases with an increasing magnetic field and above which it decreases. This behavior contrasts with the narrow MoxSi1−x meander, for which no crossover current is observed, thus suggesting different photon-detection mechanisms in the wide and narrow strips. Namely, we argue that in the wide strip the absorbed photon destroys superconductivity locally via the vortex-antivortex mechanism for the emergence of resistance, while in the narrow meander superconductivity is destroyed across the whole strip line, forming a hot belt. Accordingly, the different photon-detection mechanisms associated with vortices and the hot belt determine the qualitative difference in the dependence of the PCR on the magnetic field.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2331-7019 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1790
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Author (down) Baeva, E. M.; Titova, N. A.; Veyrat, L.; Sacépé, B.; Semenov, A. V.; Goltsman, G. N.; Kardakova, A. I.; Khrapai, V. S.
Title Thermal relaxation in metal films limited by diffuson lattice excitations of amorphous substrates Type Journal Article
Year 2021 Publication Phys. Rev. Applied Abbreviated Journal Phys. Rev. Applied
Volume 15 Issue 5 Pages 054014
Keywords InOx, Au/Ni, NbN films
Abstract We examine the role of a silicon-based amorphous insulating substrate in the thermal relaxation in thin NbN, InOx, and Au/Ni films at temperatures above 5 K. The samples studied consist of metal bridges on an amorphous insulating layer lying on or suspended above a crystalline substrate. Noise thermometry is used to measure the electron temperature Te of the films as a function of Joule power per unit area P2D. In all samples, we observe a P2D∝Tne dependence, with exponent n≃2, which is inconsistent with both electron-phonon coupling and Kapitza thermal resistance. In suspended samples, the functional dependence of P2D(Te) on the length of the amorphous insulating layer is consistent with the linear temperature dependence of the thermal conductivity, which is related to lattice excitations (diffusons) for a phonon mean free path shorter than the dominant phonon wavelength. Our findings are important for understanding the operation of devices embedded in amorphous dielectrics.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2331-7019 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1769
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Author (down) Baeva, E. M.; Sidorova, M. V.; Korneev, A. A.; Smirnov, K. V.; Divochy, A. V.; Morozov, P. V.; Zolotov, P. I.; Vakhtomin, Y. B.; Semenov, A. V.; Klapwijk, T. M.; Khrapai, V. S.; Goltsman, G. N.
Title Thermal properties of NbN single-photon detectors Type Journal Article
Year 2018 Publication Phys. Rev. Applied Abbreviated Journal Phys. Rev. Applied
Volume 10 Issue 6 Pages 064063 (1 to 8)
Keywords NbN SSPD, SNSPD
Abstract We investigate thermal properties of a NbN single-photon detector capable of unit internal detection efficiency. Using an independent calibration of the coupling losses, we determine the absolute optical power absorbed by the NbN film and, via resistive superconductor thermometry, the temperature dependence of the thermal resistance Z(T) of the NbN film. In principle, this approach permits simultaneous measurement of the electron-phonon and phonon-escape contributions to the energy relaxation, which in our case is ambiguous because of the similar temperature dependencies. We analyze Z(T) with a two-temperature model and impose an upper bound on the ratio of electron and phonon heat capacities in NbN, which is surprisingly close to a recent theoretical lower bound for the same quantity in similar devices.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2331-7019 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 1226
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