Records |
Author |
Peltonen, J. T.; Astafiev, O. V.; Korneeva, Y. P.; Voronov, B. M.; Korneev, A. A.; Charaev, I. M.; Semenov, A. V.; Golt'sman, G. N.; Ioffe, L. B.; Klapwijk, T. M.; Tsai, J. S. |
Title |
Coherent flux tunneling through NbN nanowires |
Type |
Journal Article |
Year |
2013 |
Publication |
Phys. Rev. B |
Abbreviated Journal |
Phys. Rev. B |
Volume |
88 |
Issue |
22 |
Pages |
220506 (1 to 5) |
Keywords |
NbN nanowires |
Abstract |
We demonstrate evidence of coherent magnetic flux tunneling through superconducting nanowires patterned in a thin highly disordered NbN film. The phenomenon is revealed as a superposition of flux states in a fully metallic superconducting loop with the nanowire acting as an effective tunnel barrier for the magnetic flux, and reproducibly observed in different wires. The flux superposition achieved in the fully metallic NbN rings proves the universality of the phenomenon previously reported for InOx. We perform microwave spectroscopy and study the tunneling amplitude as a function of the wire width, compare the experimental results with theories, and estimate the parameters for existing theoretical models. |
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1098-0121 |
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1369 |
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Wild, W.; Kardashev, N. S.; Likhachev, S. F.; Babakin, N. G.; Arkhipov, V. Y.; Vinogradov, I. S.; Andreyanov, V. V.; Fedorchuk, S. D.; Myshonkova, N. V.; Alexsandrov, Y. A.; Novokov, I. D.; Goltsman, G. N.; Cherepaschuk, A. M.; Shustov, B. M.; Vystavkin, A. N.; Koshelets, V. P.; Vdovin, V.F.; de Graauw, T.; Helmich, F.; vd Tak, F.; Shipman, R.; Baryshev, A.; Gao, J. R.; Khosropanah, P.; Roelfsema, P.; Barthel, P.; Spaans, M.; Mendez, M.; Klapwijk, T.; Israel, F.; Hogerheijde, M.; vd Werf, P.; Cernicharo, J.; Martin-Pintado, J.; Planesas, P.; Gallego, J. D.; Beaudin, G.; Krieg, J. M.; Gerin, M.; Pagani, L.; Saraceno, P.; Di Giorgio, A. M.; Cerulli, R.; Orfei, R.; Spinoglio, L.; Piazzo, L.; Liseau, R.; Belitsky, V.; Cherednichenko, S.; Poglitsch, A.; Raab, W.; Guesten, R.; Klein, B.; Stutzki, J.; Honingh, N.; Benz, A.; Murphy, A.; Trappe, N.; Räisänen, A. |
Title |
Millimetron—a large Russian-European submillimeter space observatory |
Type |
Journal Article |
Year |
2009 |
Publication |
Exp. Astron. |
Abbreviated Journal |
Exp. Astron. |
Volume |
23 |
Issue |
1 |
Pages |
221-244 |
Keywords |
Millimetron space observatory, VLBI, very long baseline interferometry |
Abstract |
Millimetron is a Russian-led 12 m diameter submillimeter and far-infrared space observatory which is included in the Space Plan of the Russian Federation for launch around 2017. With its large collecting area and state-of-the-art receivers, it will enable unique science and allow at least one order of magnitude improvement with respect to the Herschel Space Observatory. Millimetron will be operated in two basic observing modes: as a single-dish observatory, and as an element of a ground-space very long baseline interferometry (VLBI) system. As single-dish, angular resolutions on the order of 3 to 12 arc sec will be achieved and spectral resolutions of up to a million employing heterodyne techniques. As VLBI antenna, the chosen elliptical orbit will provide extremely large VLBI baselines (beyond 300,000 km) resulting in micro-arc second angular resolution. |
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0922-6435 |
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1402 |
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Gao, J. R.; Hajenius, M.; Tichelaar, F. D.; Klapwijk, T. M.; Voronov, B.; Grishin, E.; Gol’tsman, G.; Zorman, C. A.; Mehregany, M. |
Title |
Monocrystalline NbN nanofilms on a 3C-SiC∕Si substrate |
Type |
Journal Article |
Year |
2007 |
Publication |
Appl. Phys. Lett. |
Abbreviated Journal |
Appl. Phys. Lett. |
Volume |
91 |
Issue |
6 |
Pages |
062504 (1 to 3) |
Keywords |
NbN films, nanofilms |
Abstract |
The authors have realized NbN (100) nanofilms on a 3C-SiC (100)/Si(100) substrate by dc reactive magnetron sputtering at 800°C. High-resolution transmission electron microscopy (HRTEM) is used to characterize the films, showing a monocrystalline structure and confirming epitaxial growth on the 3C-SiC layer. A film ranging in thickness from 3.4to4.1nm shows a superconducting transition temperature of 11.8K, which is the highest reported for NbN films of comparable thickness. The NbN nano-films on 3C-SiC offer a promising alternative to improve terahertz detectors. For comparison, NbN nanofilms grown directly on Si substrates are also studied by HRTEM.
The authors acknowledge S. V. Svetchnikov at National Centre for HRTEM at Delft, who prepared the specimens for HRTEM inspections. This work was supported by the EU through RadioNet and INTAS. |
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0003-6951 |
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1425 |
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Gao, J.R.; Hiajenius, M.; Yang, Z.Q.; Klapwijk, T.M.; Miao, W.; Shi, S. C.; Voronov, B.; Gortsman, G. |
Title |
Direct comparison of the sensitivity of a spiral and a twin-slot antenna coupled HEB mixer at 1.6 THz |
Type |
Conference Article |
Year |
2006 |
Publication |
Proc. 17th Int. Symp. Space Terahertz Technol. |
Abbreviated Journal |
Proc. 17th Int. Symp. Space Terahertz Technol. |
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Pages |
59-62 |
Keywords |
NbN HEB mixers |
Abstract |
To make a direct comparison of the sensitivity between a spiral and a twin slot antenna coupled HEB mixer, we designed both types of mixers and fabricated them in a single processing run and on the same wafer. Both mixers have similar dimensions of NbN bridges (1.5-2 pm x0.2 pm). At 1.6 THz we obtained a nearly identical receiver noise temperature from both mixers (only 5% difference), which is in a good agreement with the simulation based on semi analytical models for both antennas. In addition, by using a bandpass filter to reduce the direct detection effect and lowering the bath temperature to 2.4 K, we measured the lowest receiver noise temperature of 700 K at 1.63 THz using the twin-slot antenna mixer. |
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1436 |
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Baselmans, J. J. A.; Baryshev, A.; Hajenius, M.; Gao, J. R.; Klapwijk, T. M.; Voronov, B.; Gol'tsman, G. |
Title |
Influence of the direct response on the heterodyne sensitivity of hot electron bolometer mixers |
Type |
Abstract |
Year |
2006 |
Publication |
Proc. 17th Int. Symp. Space Terahertz Technol. |
Abbreviated Journal |
Proc. 17th Int. Symp. Space Terahertz Technol. |
Volume |
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Issue |
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Pages |
81 |
Keywords |
NbN HEB mixers |
Abstract |
We present a detailed experimental study of the direct detection effect in a small volume (0.15pm x lpm) NbN hot electron bolometer mixer. It is a quasioptical mixer with a twin slot antenna designed for 700 GHz and the measurement was done at a LO frequency of 670 GHz. The direct detection effect is characterized by a change in the mixer bias current when switching broadband radiation from a 300 K hot load to a 77 K cold load in a standard Y factor measurement. The result is, depending on the receiver under study, an increase or decrease in the receiver noise temperature. We find that the small signal noise temperature, which is the noise temperature that would be observed without the presence of the direct detection effect, and thus the one that is relevant for an astronomical observation, is 20% lower than the noise temperature obtained using 300 K and 77 K calibration loads. Thus, in our case the direct detection effect reduces the mixer sensitivity. These results are in good agreement with previous measurement at THz frequencies [1]. Other experiments report an increase in mixer sensitivity [2]. To analyze this discrepancy we have designed a separate set of experiments to find out the physical origin of the direct detection effect. Possible candidates are the bias current dependence of the mixer gain and the bias current dependence of the IF match. We measured directly the change in mixer IF match and receiver gain due to the direct detection effect. From these measurements we conclude that the direct detection effect is caused by a combination of bias current reduction when switching form the 77 K to the 300 K load in combination with the bias current dependence of the receiver gain. The bias current dependence of the receiver gain is shown to be mainly caused by the current dependence of the mixer gain. We also find that an increase in receiver sensitivity due to the direct detection effect is only possible if the noise temperature change due to the direct detection is dominated by the mixer-amplifier IF match. [1] J.J.A. Baselmans, A. Baryshev, S.F. Reker, M. Hajenius, J.R. Gao, T.M. Klapwijk, Yu.Vachtomin, S. Maslennikov, S. Antipov, B. Voronov, and G. Gol'tsman., Appl. Phys. Lett. 86, 163503 (2005). [2] S. Svechnokov, A. Verevkin, B. Voronov, E. Menschikov. E. Gershenzon, G. Gol'tsman, 9th Int. Symp. On Space THz. Techn., 45, (1999). |
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1437 |
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