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44 results on '"Kinev, N."'

3. Thermal and electromagnetic properties of Bi$_2$Sr$_2$CaCu$_2$O$_8$ intrinsic Josephson junction stacks studied via one-dimensional coupled sine-Gordon equations

Author

Rudau, F., Tsujimoto, M., Gross, B., Judd, T. E., Wieland, R., Goldobin, E., Kinev, N., Yuan, J., Huang, Y., Ji, M., Zhou, X. J., An, D. Y., Ishii, A., Mints, R. G., Wu, P. H., Hatano, T., Wang, H. B., Koshelets, V. P., Koelle, D., and Kleiner, R.

Subjects
Condensed Matter - Superconductivity
Abstract

We used one-dimensional coupled sine-Gordon equations combined with heat diffusion equations to numerically investigate the thermal and electromagnetic properties of a $300\,\mu\mathrm{m}$ long intrinsic Josephson junction stack consisting of $N = 700$ junctions. The junctions in the stack are combined to $M$ segments where we assume that inside a segment all junctions behave identically. Most simulations are for $M = 20$. For not too high bath temperatures there is the appearence of a hot spot at high bias currents. In terms of electromagnetic properties, robust standing wave patterns appear in the current density and electric field distributions. These patterns come together with vortex/antivortex lines across the stack that correspond to $\pi$ kink states, discussed before in the literature for a homogeneous temperature distribution in the stack. We also discuss scaling of the thermal and electromagnetic properties with $M$, on the basis of simulations with $M$ between 10 and 350., Comment: 17 pages, 17 figures

Published
2014
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7. Modeling the linewidth dependence of coherent terahertz emission from intrinsic Josephson junction stacks in the hot-spot regime

Author

Gross, B., Yuan, J., An, D. Y., Li, M. Y., Kinev, N., Zhou, X. J., Ji, M., Huang, Y., Hatano, T., Mints, R. G., Koshelets, V. P., Wu, P. H., Wang, H. B., Koelle, D., and Kleiner, R.

Subjects
Condensed Matter - Superconductivity
Abstract

Recently it has been found that, when operated at large input power, the linewidth of terahertz radiation emitted from intrinsic Josephson junction stacks can be as narrow as some megahertz. In this high-bias regime a hot spot coexists with regions which are still superconducting. Surprisingly, the linewidth was found to decrease with increasing bath temperature. We present a simple model describing the dynamics of the stack in the presence of a hot spot by two parallel arrays of pointlike Josephson junctions and an additional shunt resistor in parallel. Heat diffusion is taken into account by thermally coupling all elements to a bath at temperature T_b. We present current-voltage characteristics of the coupled system and calculations of the linewidth of the radiation as a function of T_b. In the presence of a spatial gradient of the junction parameters critical current and resistance, the linewidth deceases with increasing T_b, similar to the experimental observation., Comment: accepted in PRB

Published
2013

8. Unusual linewidth dependence of coherent THz emission measured from intrinsic Josephson junction stacks in the hot-spot regime

Author

Li, M. Y., Yuan, J., Kinev, N., Li, J., Gross, B., Guenon, S., Ishii, A., Hirata, K., Hatano, T., Koelle, D., Kleiner, R., Koshelets, V. P., Wang, H. B., and Wu, P. H.

Subjects
Condensed Matter - Superconductivity, Physics - Instrumentation and Detectors
Abstract

We report on measurements of the linewidth {\Delta}f of THz radiation emitted from intrinsic Josephson junction stacks, using a Nb/AlN/NbN integrated receiver for detection. Previous resolution limited measurements indicated that {\Delta}f may be below 1 GHz - much smaller than expected from a purely cavity-induced synchronization. While at low bias we found {\Delta}f to be not smaller than ? 500 MHz, at high bias, where a hotspot coexists with regions which are still superconducting, {\Delta}f turned out to be as narrow as 23 MHz. We attribute this to the hotspot acting as a synchronizing element. {\Delta}f decreases with increasing bath temperature, a behavior reminiscent of motional narrowing in NMR or ESR, but hard to explain in standard electrodynamic models of Josephson junctions., Comment: 4 figures, 5 pages

Published
2012
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12. Flux-flow Josephson oscillator as the broadband tunable terahertz source to open space.

Author

Kinev, N. V., Rudakov, K. I., Filippenko, L. V., Baryshev, A. M., and Koshelets, V. P.

Subjects
*JOSEPHSON junctions, *JOSEPHSON effect, *BROADBAND communication systems, *HARMONIC oscillators, *OSCILLATIONS
Abstract

The flux-flow oscillator (FFO) based on a long Josephson junction has been implemented as a broadband tunable terahertz (THz) source to open space. For this purpose, the transmitting slot antenna has been coupled to the oscillator. Additionally, an elliptical lens with a diameter of 10 mm has been matched to the antenna, forming a narrow output beam of the THz emission. Two designs for the antenna, integrated with the oscillator and developed for operation at different frequency ranges of 0.32–0.55 THz and 0.4–0.7 THz, have been investigated. The FFO has been phase locked to an external reference oscillator by utilizing a harmonic mixer. Its linewidth in the phase-locking regime is determined by the phase noise of the reference oscillator and the number of harmonics used and has been measured to be less than 0.1 MHz. A free-running FFO linewidth from about 2 MHz to several MHz, depending on the operating point, has been obtained. Output emission to open space has been measured by a superconducting integrated spectrometer located in a separate cryostat. The FFO operation as an external source with the achieved emission power and spectral characteristics has demonstrated its applicability for different tasks and purposes where tunable THz sources are required. [ABSTRACT FROM AUTHOR]

Published
2019
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14. Study of Josephson Generation Harmonics in a Long Josephson Junction.

Author

Kinev, N. V., Rudakov, K. I., Filippenko, L. V., and Koshelets, V. P.

Subjects
*JOSEPHSON junctions, *JOSEPHSON effect, *SEMICONDUCTOR detectors, *FOURIER transform spectrometers, *TERAHERTZ materials, *TRANSMITTING antennas, *SUBMILLIMETER waves, *INTEGRATED circuits
Abstract

We present the results of experimental study of the harmonics of Josephson radiation from a terahertz (THz) source based on a long Josephson junction (LJJ). The source consists of an integrated circuit including the LJJ, a matched transmitting antenna, and a harmonic mixer used for phase locking of the output signal. The LJJ and the harmonic mixer are both made of three-layer Nb-AlOx-Nb superconductor–insulator–superconductor (SIS) structures and operate at a temperature of 4.2 K. The antenna is located in the base superconducting Nb electrode of the microcircuit. To study the spectral composition and characteristics of the output radiation, two different methods were employed, using a THz Fourier transform spectrometer based on a broadband semiconductor detector and using a high-resolution THz spectrometer based on a heterodyne SIS receiver. The spectral composition of the radiation demonstrates the presence of both the fundamental harmonic of the Josephson effect and the higher harmonics. The spectral characteristics of the fundamental (at frequencies of 300–335 GHz) and the second (at frequencies of 600–670 GHz) harmonics, respectively, with a spectral resolution of about 0.1 MHz were studied using a SIS detector. [ABSTRACT FROM AUTHOR]

Published
2023
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19. Tuning Thz Emission Properties Of Bi2Sr2Cacu2O8+Delta Intrinsic Josephson Junction Stacks By Charge Carrier Injection

Author

Kizilaslan, O., Rudau, F., Wieland, R., Hampp, J. S., Zhou, X. J., Ji, M., Kiselev, O., Kinev, N., Huang, Y., Hao, L. Y., Ishii, A., Aksan, M. A., Hatano, T., Koshelets, V. P., Wu, P. H., Wang, H. B., Dieter Koelle, and Kleiner, R.

Subjects
Condensed Matter::Materials Science, Condensed Matter::Superconductivity, Physics::Optics, Condensed Matter::Strongly Correlated Electrons
Abstract

We report on doping and undoping experiments of terahertz (THz) emitting intrinsic Josephson junction stacks, where the change in charge carrier concentration is achieved by heavy current injection. The experiments were performed on stand-alone structures fabricated from a Bi2Sr2CaCu2O8+delta single crystal near optimal doping. The stacks contained about 930 intrinsic Josephson junctions. On purpose, the doping and undoping experiments were performed over only a modest range of charge carrier concentrations, changing the critical temperature of the stack by less than 1 K. We show that both undoping and doping is feasible also for the large intrinsic Josephson junction stacks used for THz generation. Even moderate changes in doping introduce large changes in the THz emission properties of the stacks. The highest emission power was achieved after doping a pristine sample.

Published
2017

20. Tuning THz emission properties of Bi2Sr2CaCu2O8+δintrinsic Josephson junction stacks by charge carrier injection

Author

Kizilaslan, O, primary, Rudau, F, additional, Wieland, R, additional, Hampp, J S, additional, Zhou, X J, additional, Ji, M, additional, Kiselev, O, additional, Kinev, N, additional, Huang, Y, additional, Hao, L Y, additional, Ishii, A, additional, Aksan, M A, additional, Hatano, T, additional, Koshelets, V P, additional, Wu, P H, additional, Wang, H B, additional, Koelle, D, additional, and Kleiner, R, additional

Published
2017
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23. Three-Dimensional Simulations of the Electrothermal and Terahertz Emission Properties ofBi2Sr2CaCu2O8Intrinsic Josephson Junction Stacks

Author

Rudau, F., primary, Wieland, R., additional, Langer, J., additional, Zhou, X. J., additional, Ji, M., additional, Kinev, N., additional, Hao, L. Y., additional, Huang, Y., additional, Li, J., additional, Wu, P. H., additional, Hatano, T., additional, Koshelets, V. P., additional, Wang, H. B., additional, Koelle, D., additional, and Kleiner, R., additional

Published
2016
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24. Tuning the Terahertz Emission Power of an Intrinsic Josephson-Junction Stack with a Focused Laser Beam

Author

Zhou, X. J., primary, Yuan, J., additional, Wu, H., additional, Gao, Z. S., additional, Ji, M., additional, An, D. Y., additional, Huang, Y., additional, Rudau, F., additional, Wieland, R., additional, Gross, B., additional, Kinev, N., additional, Li, J., additional, Ishii, A., additional, Hatano, T., additional, Koshelets, V. P., additional, Koelle, D., additional, Kleiner, R., additional, Wang, H. B., additional, and Wu, P. H., additional

Published
2015
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25. Electrothermal behavior and terahertz emission properties of a planar array of two Bi2Sr2CaCu2O8+δintrinsic Josephson junction stacks

Author

Gross, B, primary, Rudau, F, additional, Kinev, N, additional, Tsujimoto, M, additional, Yuan, J, additional, Huang, Y, additional, Ji, M, additional, Zhou, X J, additional, An, D Y, additional, Ishii, A, additional, Wu, P H, additional, Hatano, T, additional, Koelle, D, additional, Wang, H B, additional, Koshelets, V P, additional, and Kleiner, R, additional

Published
2015
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26. Thermal and electromagnetic properties ofBi2Sr2CaCu2O8intrinsic Josephson junction stacks studied via one-dimensional coupled sine-Gordon equations

Author

Rudau, F., primary, Tsujimoto, M., additional, Gross, B., additional, Judd, T. E., additional, Wieland, R., additional, Goldobin, E., additional, Kinev, N., additional, Yuan, J., additional, Huang, Y., additional, Ji, M., additional, Zhou, X. J., additional, An, D. Y., additional, Ishii, A., additional, Mints, R. G., additional, Wu, P. H., additional, Hatano, T., additional, Wang, H. B., additional, Koshelets, V. P., additional, Koelle, D., additional, and Kleiner, R., additional

Published
2015
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27. Compact Superconducting Terahertz Source Operating in Liquid Nitrogen

Author

Hao, L. Y., primary, Ji, M., additional, Yuan, J., additional, An, D. Y., additional, Li, M. Y., additional, Zhou, X. J., additional, Huang, Y., additional, Sun, H. C., additional, Zhu, Q., additional, Rudau, F., additional, Wieland, R., additional, Kinev, N., additional, Li, J., additional, Xu, W. W., additional, Jin, B. B., additional, Chen, J., additional, Hatano, T., additional, Koshelets, V. P., additional, Koelle, D., additional, Kleiner, R., additional, Wang, H. B., additional, and Wu, P. H., additional

Published
2015
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28. Bi2Sr2CaCu2O8 intrinsic Josephson junction stacks with improved cooling: Coherent emission above 1 THz

Author

Ji, M., primary, Yuan, J., additional, Gross, B., additional, Rudau, F., additional, An, D. Y., additional, Li, M. Y., additional, Zhou, X. J., additional, Huang, Y., additional, Sun, H. C., additional, Zhu, Q., additional, Li, J., additional, Kinev, N., additional, Hatano, T., additional, Koshelets, V. P., additional, Koelle, D., additional, Kleiner, R., additional, Xu, W. W., additional, Jin, B. B., additional, Wang, H. B., additional, and Wu, P. H., additional

Published
2014
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29. A grain boundary Josephson junction as a mixer to evaluate terahertz emission from intrinsic Josephson junctions

Author

An, D. Y., primary, Ji, M., additional, Zhou, X. J., additional, Huang, Y., additional, Yu, M., additional, Zhang, M. Y., additional, Hatano, T., additional, Kinev, N., additional, Koshelets, V. P., additional, Koelle, D., additional, Kleiner, R., additional, Chen, J., additional, Xu, W. W., additional, Wang, H. B., additional, and Wu, P. H., additional

Published
2014
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31. Superconducting integrated terahertz receivers

Author

Koshelets, V P, primary, Ermakov, A B, additional, Filippenko, L V, additional, Fomisky, M Yu, additional, Kinev, N V, additional, Kiselev, O S, additional, de Lange, A, additional, de Lange, G, additional, Rudakov, K E, additional, Torgashin, M Yu, additional, Vaks, V L, additional, Yuan, J, additional, and Wang, H B, additional

Published
2014
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32. Evaluation of terahertz emission from intrinsic josephson junctions using a high-Tc superconductor grain boundary Josephson junction

Author

An, D. Y., primary, Yuan, J., additional, Kinev, N., additional, Li, M. Y., additional, Zhou, X. J., additional, Ji, M., additional, Huang, Y., additional, Hatano, T., additional, Koshelets, V. P., additional, Koelle, D., additional, Kleiner, R., additional, Xu, W. W., additional, Wang, H. B., additional, and Wu, P. H., additional

Published
2013
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34. Modeling the linewidth dependence of coherent terahertz emission from intrinsic Josephson junction stacks in the hot-spot regime

Author

Gross, B., primary, Yuan, J., additional, An, D. Y., additional, Li, M. Y., additional, Kinev, N., additional, Zhou, X. J., additional, Ji, M., additional, Huang, Y., additional, Hatano, T., additional, Mints, R. G., additional, Koshelets, V. P., additional, Wu, P. H., additional, Wang, H. B., additional, Koelle, D., additional, and Kleiner, R., additional

Published
2013
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35. Terahertz emission and detection both based on high-Tc superconductors: Towards an integrated receiver

Author

An, D. Y., primary, Yuan, J., additional, Kinev, N., additional, Li, M. Y., additional, Huang, Y., additional, Ji, M., additional, Zhang, H., additional, Sun, Z. L., additional, Kang, L., additional, Jin, B. B., additional, Chen, J., additional, Li, J., additional, Gross, B., additional, Ishii, A., additional, Hirata, K., additional, Hatano, T., additional, Koshelets, V. P., additional, Koelle, D., additional, Kleiner, R., additional, Wang, H. B., additional, Xu, W. W., additional, and Wu, P. H., additional

Published
2013
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38. Bi2Sr2CaCu2O8 intrinsic Josephson junction stacks with improved cooling: Coherent emission above 1 THz.

Author

Yuan, J., Gross, B., Rudau, F., An, D. Y., Li, M. Y., Zhou, X. J., Huang, Y., Sun, H. C., Zhu, Q., Li, J., Kinev, N., Hatano, T., Koshelets, V. P., Xu, W. W., Jin, B. B., Wang, H. B., and Wu, P. H.

Subjects
BISMUTH strontium calcium copper oxide, TERAHERTZ technology, JOSEPHSON junctions, INTRINSIC semiconductors, SUPERCONDUCTORS
Abstract

We report on Bi2Sr2CaCu2O8 (BSCCO) intrinsic Josephson junction stacks with improved cooling, allowing for a remarkable increase in emission frequency compared to the previous designs. We started with a BSCCO stack embedded between two gold layers. When mounted in the standard way to a single substrate, the stack emits in the range of 0.43-0.82 THz. We then glued a second, thermally anchored substrate onto the sample surface. The maximum voltage of this better cooled and dimension-unchanged sample was increased and, accordingly, both the emission frequencies and the tunable frequency range were significantly increased up to 1.05 THz and to 0.71 THz, respectively. This double sided cooling may also be useful for other "hot" devices, e.g., quantum cascade lasers. [ABSTRACT FROM AUTHOR]

Published
2014
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44. Thermal and electromagnetic properties of Bi2Sr2CaCu2O8 intrinsic Josephson junction stacks studied via one-dimensional coupled sine-Gordon equations.

Author

Rudau, F., Tsujimoto, M., Gross, B., Judd, T. E., Wieland, R., Goldobin, E., Kinev, N., Yuan, J., Huang, Y., Ji, M., Zhou, X. J., An, D. Y., Ishii, A., Mints, R. G., Wu, P. H., Hatano, T., Wang, H. B., Koshelets, V. P., Koelle, D., and Kleiner, R.

Subjects
*JOSEPHSON junctions, *HEAT equation, *TEMPERATURE distribution, *TEMPERATURE, *ELECTROMAGNETISM, *SIMULATION methods & models
Abstract

We used one-dimensional coupled sine-Gordon equations combined with heat diffusion equations to numerically investigate the thermal and electromagnetic properties of a 300 pm long intrinsic Josephson junction stack consisting of N = 700 junctions. The junctions in the stack are combined with M segments where we assume that inside a segment all junctions behave identically. Most simulations are for M = 20. For not too high bath temperatures there is the appearance of a hot spot at high-bias currents. In terms of electromagnetic properties, robust standing-wave patterns appear in the current density and electric field distributions. These patterns come together with vortex/antivortex lines across the stack that correspond to jr-kink states, discussed before in the literature for a homogeneous temperature distribution in the stack. We also discuss scaling of the thermal and electromagnetic properties with M, on the basis of simulations with M between 10 and 350. [ABSTRACT FROM AUTHOR]

Published
2015
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