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ENLIGHTEN (Jurnal Bimbingan dan Konseling Islam)

Study of the radiation line width and shape from the Bi2212 mesa structure

Takanari Kashiwagi, Takashi Yamamoto, Kazuya Ishida, Manabu Tsujimoto, Kaveh Delfanazari, Ryo Nakayama, Takeo Kitamura, Masashi Sawamura, Hidehiro Asai, Hidetoshi Minami, Kazuo Kadowaki

Published Mar 1, 2012• 0 citations
OpenAlex

Abstract

Continuous electromagnetic waves in terahertz (THz) range have been observed from mesa structures of Bi2Sr2CaCu2O8+δ(Bi2212) single crystals^1) It has been established that the radiation frequency is determined by both the ac Josephson frequency and the resonance condition of the geometrical cavity^2). In order to understand the mechanism of the radiation from the intrinsic Josephson junctions (IJJs) in Bi2212, we studied the radiation line width and shape. These might depend upon the physical parameters of the Bi2212 single crystal such as the number of IJJs the fluctuations of the quasiparticles and pairs, the non-linearity and non-equilibrium conditions, and the stability of the electrical circuit including the IJJs. However, technical difficulties have been delayed the line width measurements in the THz range. Recently, we succeeded in measuring the radiation line width using a frequency mixer. These results will be compared to those from a single junction 1) L. Ozyuzer et al., Science 318 (2007) 1291., 2) K. Kadowaki et al., J. Phys. Soc. Jpn. 79 (2010) 023703

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Coherent THz-wave emission from voltage-and number-controlled intrinsic Josephson junctions in Bi-2212

Manabu Tsujimoto, Ryo Nakayama, Naoki Orita +7 more

Intense and coherent terahertz electromagnetic wave (THz-wave) emission from the intrinsic Josephson junctions (IJJs) in single crystalline high-Tc superconductor Bi2Sr2CaCu2O8+δ (Bi-2212) was reported in 2007 [L. Ozyuzer \\textit{et al}., Science \\textbf{318}, (2007) 1291.]. In the present work, we demonstrate the relationship between the bias condition and the resonance state by controlling both the applied voltage, V, and the number of resistive junctions, N. We directly observed that if N junctions are in resistive state, the resonance frequency, fJ, varies in accordance with the ac-Josephson relation; fJ = (2|e|/h)V/N, although frequency fJ has previously been thought to be uniquely determined by the geometrical condition due to the cavity resonance effect [M. Tsujimoto \\textit{et al}., Phys. Rev. Lett. \\textbf{105}, (2010) 037005.]. We also found that the emission intensity varies as a function of both fJ and N. *CREST-JST, WPI-MANA, Strategic Initiative A (University of Tsukuba)

ENLIGHTEN (Jurnal Bimbingan dan Konseling Islam)•Mar 21, 2011•0 citations

Coherent emission from the intrinsic Josephson junctions in thermally-managed, high-symmetry Bi2Sr2CaCu2O8+δ devices

Richard A. Klemm, Daniel Cerkoney, Constance M. Doty +14 more

The emission of coherent radiation from the intrinsic Josephson junctions in the high transition temperature Tc superconductor Bi2Sr2CaCu2O8+δ (Bi2212) arises from two sources: (1) the uniform part of the ac Josephson current satisfying the Josephson relation f = fJ = 2ev/h, where e is the electronic charge, v is the applied voltage per junction, and h is Planck's constant, and (2) when f = fc (n,m) matches that of the (n,m) the electromagnetic geometrical cavity mode of the thin device, the emission power can be greatly enhanced [1]. For conventional devices such as mesas carved from the top of a Bi2212 single crystal [2,4], the Bi2212 substrate not only absorbs much of the emission nearly parallel to the substrate [1], but its poor thermal conductivity leads to Joule heating,f < 1THz, and the inevitable formation of hot spots, inside of which the local temperature T(r) > Tc [5]. However, “thermally-managedstand-alone” devices constructed by removing the mesa from its Bi2212 substrate, covering its top and bottom surfaces with Au and sandwiching it between sapphire plates [3,6], narrow-linewidth emission at the world-record 2.4 THz from a superconductor was observed [7], placing a lower limit of ∆min ≥ 9.8meV on the bulk Bi2212 gap function, and filling the “THz gap” with a tunable, continuous-wave emitter. Moreover, the emission spectra from that high-symmetry disk [7] and unpublished high-symmetry square devices strongly suggest that only cavity modes obtained from wave functions that are one-dimensional representations of the appropriate point group can lead to electromagnetic cavity mode enhancements [3,7-9]. A theoretical explanation of this previously unknown restriction is presented. [1] R.A.Klemm and K.Kadowaki, J. Phys.: Condens. Matter 22, 375701 (2010). [2] M. Tsujimoto et al., Phys. Rev. Lett. 105, 037005 (2010). [3] M. Tsujimoto et al., Phys. Rev. Lett. 108, 107006 (2012). [4] K. Delfanazari et al., Opt. Express 21, 2171 (2013). [5] H. Minami et al., Phys. Rev. B 89, 054503 (2014). [6] T. Kashiwagi et al., Phys. Rev. Applied 4, 054018 (2015). [7] T. Kashiwagi et al., Appl. Phys. Lett.107, 082601 (2015). [8] D. P. Cerkoney et al., J. Phys.: Condens. Matter 29, 015601 (2017). [9] R. A. Klemm, A. E. Davis, and Q. X. Wang, IEEE J. Sel. Top. Quant. Electron.(2017, inpress) DOI 10.1109/JSTQE.2017.2649459

ENLIGHTEN (Jurnal Bimbingan dan Konseling Islam)•May 1, 2017•0 citations

Excitation mode characteristics in Bi2212 rectangular mesa structures

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The rectangular mesa structure of single crystalline Bi 2 Sr 2 CaCu 2 O 8+δ with the dimensions of 64 × 135 × 1.35 μ m 3 was fabricated by using Ar-ion milling with a metallic mask and focused ion beam. From this mesa, the radiation frequencies of 24.226 cm −1 and 17.296 cm −1 were observed at the different temperatures of 25 K and 40 K, respectively. The change of the radiation frequencies is also obviously reflected in the radiation pattern measurement. The radiation pattern observed at lower temperature seems to have an asymmetric shape and its intensity as a whole is slightly weak. In the higher temperature, however, the radiation intensity increases and the radiation pattern becomes almost symmetric shape. The radiation characteristics observed at higher temperature is well explained by the fundamental cavity resonance mode expected from the width of the mesa. This result may give us not only the suggestion of the existence of the adequate matching condition between the geometrical cavity and the ac Josephson current in the mesa but also the guide for the designing of the high efficiency of the radiation.

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E. A. Borodianskyi, V. M. Krasnov

high-temperature superconductor represent stacks of atomic scale intrinsic Josephson junctions. They can be used for generation of high-frequency electromagnetic waves. Here we analyze Josephson emission from small-but-high mesas (with a small area, but containing many stacked junctions). We have found strong evidence for tunable terahertz emission with a good efficacy in a record high-frequency span 1-11 THz, approaching the theoretical upper limit for this superconductor. Emission maxima correspond to in-phase cavity modes in the mesas, indicating coherent superradiant nature of the emission. We conclude that terahertz emission requires a threshold number of junctions N ~ 100. The threshold behavior is not present in the classical description of stacked Josephson junctions and suggests importance of laser-like cascade amplification of the photon number in the cavity.

Nature Communications•Nov 17, 2017•80 citations

Terahertz Radiations and Switching Phenomena of Intrinsic Josephson Junctions in High-Temperature Superconductors: Josephson Phase Dynamics in Long- and Short-Ranged Interactions

Itsuhiro Kakeya

Studies on intrinsic Josephson junctions (IJJs) of cuprate superconductors are reviewed. A system consisting of a few IJJs provides phenomena to test the Josephson phase dynamics and its interaction between adjacent IJJs within a nanometer scale, which is unique to cuprate superconductors. Quasiparticle density of states, which provides direct information on the Cooper-pair formation, is also revealed in the system. In contrast, Josephson plasma emission, which is an electromagnetic wave radiation in the sub-terahertz frequency range from an IJJ stack, arises from the synchronous phase dynamics of hundreds of IJJs coupled globally. This review summarizes a wide range of physical phenomena in IJJ systems having capacitive and inductive couplings with different nanometer and micrometer length scales, respectively.

IEICE Transactions on Electronics•Dec 6, 2022•1 citation

Microwave-induced current steps in intrinsic Josephson junctions patterned on Bi2Sr2CaCu2O8 single crystal

H.B. Wang, Yuta Aruga, Takashi Tachiki +5 more

With a 10 μm×10 μm mesa patterned on Bi2Sr2CaCu2O8 single crystals, we measure the current–voltage (I–V) curves of a stack of intrinsic Josephson junctions. Current steps are observed at an equal voltage spacing of 4 mV when the sample is subjected to microwave radiation at around 7 GHz. With increase of the microwave power, more steps occur while the spacing between neighboring steps does not seem to change. The magnitude of each step depends on the microwave power in an oscillating way. Tuning the microwave frequency causes such steps to occur over separate frequency ranges, and each range is quite narrow. A temperature rise from 4.2 to 14.3 K completely quenches the step structures. Possible explanations for the step structures, based on resonances excited by microwave or geometric resonances in the junction cavity, are discussed.

Applied Physics Letters•Jun 14, 1999•19 citations
Continuous electromagnetic waves in terahertz (THz) range have been observed from mesa structures of Bi2Sr2CaCu2O8+δ(Bi2212) single crystals^1) It has been established that the radiation frequency is determined by both the ac Josephson frequency and the resonance condition of the geometrical cavity^2). In order to understand the mechanism of the radiation from the intrinsic Josephson junctions (IJJs) in Bi2212, we studied the radiation line width and shape. These might depend upon the physical parameters of the Bi2212 single crystal such as the number of IJJs the fluctuations of the quasiparticles and pairs, the non-linearity and non-equilibrium conditions, and the stability of the electrical circuit including the IJJs. However, technical difficulties have been delayed the line width measurements in the THz range. Recently, we succeeded in measuring the radiation line width using a frequency mixer. These results will be compared to those from a single junction 1) L. Ozyuzer et al., Science 318 (2007) 1291., 2) K. Kadowaki et al., J. Phys. Soc. Jpn. 79 (2010) 023703
Intense and coherent terahertz electromagnetic wave (THz-wave) emission from the intrinsic Josephson junctions (IJJs) in single crystalline high-Tc superconductor Bi2Sr2CaCu2O8+δ (Bi-2212) was reported in 2007 [L. Ozyuzer \\textit{et al}., Science \\textbf{318}, (2007) 1291.]. In the present work, we demonstrate the relationship between the bias condition and the resonance state by controlling both the applied voltage, V, and the number of resistive junctions, N. We directly observed that if N junctions are in resistive state, the resonance frequency, fJ, varies in accordance with the ac-Josephson relation; fJ = (2|e|/h)V/N, although frequency fJ has previously been thought to be uniquely determined by the geometrical condition due to the cavity resonance effect [M. Tsujimoto \\textit{et al}., Phys. Rev. Lett. \\textbf{105}, (2010) 037005.]. We also found that the emission intensity varies as a function of both fJ and N. *CREST-JST, WPI-MANA, Strategic Initiative A (University of Tsukuba)
The emission of coherent radiation from the intrinsic Josephson junctions in the high transition temperature Tc superconductor Bi2Sr2CaCu2O8+δ (Bi2212) arises from two sources: (1) the uniform part of the ac Josephson current satisfying the Josephson relation f = fJ = 2ev/h, where e is the electronic charge, v is the applied voltage per junction, and h is Planck's constant, and (2) when f = fc (n,m) matches that of the (n,m) the electromagnetic geometrical cavity mode of the thin device, the emission power can be greatly enhanced [1]. For conventional devices such as mesas carved from the top of a Bi2212 single crystal [2,4], the Bi2212 substrate not only absorbs much of the emission nearly parallel to the substrate [1], but its poor thermal conductivity leads to Joule heating,f < 1THz, and the inevitable formation of hot spots, inside of which the local temperature T(r) > Tc [5]. However, “thermally-managedstand-alone” devices constructed by removing the mesa from its Bi2212 substrate, covering its top and bottom surfaces with Au and sandwiching it between sapphire plates [3,6], narrow-linewidth emission at the world-record 2.4 THz from a superconductor was observed [7], placing a lower limit of ∆min ≥ 9.8meV on the bulk Bi2212 gap function, and filling the “THz gap” with a tunable, continuous-wave emitter. Moreover, the emission spectra from that high-symmetry disk [7] and unpublished high-symmetry square devices strongly suggest that only cavity modes obtained from wave functions that are one-dimensional representations of the appropriate point group can lead to electromagnetic cavity mode enhancements [3,7-9]. A theoretical explanation of this previously unknown restriction is presented. [1] R.A.Klemm and K.Kadowaki, J. Phys.: Condens. Matter 22, 375701 (2010). [2] M. Tsujimoto et al., Phys. Rev. Lett. 105, 037005 (2010). [3] M. Tsujimoto et al., Phys. Rev. Lett. 108, 107006 (2012). [4] K. Delfanazari et al., Opt. Express 21, 2171 (2013). [5] H. Minami et al., Phys. Rev. B 89, 054503 (2014). [6] T. Kashiwagi et al., Phys. Rev. Applied 4, 054018 (2015). [7] T. Kashiwagi et al., Appl. Phys. Lett.107, 082601 (2015). [8] D. P. Cerkoney et al., J. Phys.: Condens. Matter 29, 015601 (2017). [9] R. A. Klemm, A. E. Davis, and Q. X. Wang, IEEE J. Sel. Top. Quant. Electron.(2017, inpress) DOI 10.1109/JSTQE.2017.2649459
The rectangular mesa structure of single crystalline Bi 2 Sr 2 CaCu 2 O 8+δ with the dimensions of 64 × 135 × 1.35 μ m 3 was fabricated by using Ar-ion milling with a metallic mask and focused ion beam. From this mesa, the radiation frequencies of 24.226 cm −1 and 17.296 cm −1 were observed at the different temperatures of 25 K and 40 K, respectively. The change of the radiation frequencies is also obviously reflected in the radiation pattern measurement. The radiation pattern observed at lower temperature seems to have an asymmetric shape and its intensity as a whole is slightly weak. In the higher temperature, however, the radiation intensity increases and the radiation pattern becomes almost symmetric shape. The radiation characteristics observed at higher temperature is well explained by the fundamental cavity resonance mode expected from the width of the mesa. This result may give us not only the suggestion of the existence of the adequate matching condition between the geometrical cavity and the ac Josephson current in the mesa but also the guide for the designing of the high efficiency of the radiation.
high-temperature superconductor represent stacks of atomic scale intrinsic Josephson junctions. They can be used for generation of high-frequency electromagnetic waves. Here we analyze Josephson emission from small-but-high mesas (with a small area, but containing many stacked junctions). We have found strong evidence for tunable terahertz emission with a good efficacy in a record high-frequency span 1-11 THz, approaching the theoretical upper limit for this superconductor. Emission maxima correspond to in-phase cavity modes in the mesas, indicating coherent superradiant nature of the emission. We conclude that terahertz emission requires a threshold number of junctions N ~ 100. The threshold behavior is not present in the classical description of stacked Josephson junctions and suggests importance of laser-like cascade amplification of the photon number in the cavity.
Studies on intrinsic Josephson junctions (IJJs) of cuprate superconductors are reviewed. A system consisting of a few IJJs provides phenomena to test the Josephson phase dynamics and its interaction between adjacent IJJs within a nanometer scale, which is unique to cuprate superconductors. Quasiparticle density of states, which provides direct information on the Cooper-pair formation, is also revealed in the system. In contrast, Josephson plasma emission, which is an electromagnetic wave radiation in the sub-terahertz frequency range from an IJJ stack, arises from the synchronous phase dynamics of hundreds of IJJs coupled globally. This review summarizes a wide range of physical phenomena in IJJ systems having capacitive and inductive couplings with different nanometer and micrometer length scales, respectively.
With a 10 μm×10 μm mesa patterned on Bi2Sr2CaCu2O8 single crystals, we measure the current–voltage (I–V) curves of a stack of intrinsic Josephson junctions. Current steps are observed at an equal voltage spacing of 4 mV when the sample is subjected to microwave radiation at around 7 GHz. With increase of the microwave power, more steps occur while the spacing between neighboring steps does not seem to change. The magnitude of each step depends on the microwave power in an oscillating way. Tuning the microwave frequency causes such steps to occur over separate frequency ranges, and each range is quite narrow. A temperature rise from 4.2 to 14.3 K completely quenches the step structures. Possible explanations for the step structures, based on resonances excited by microwave or geometric resonances in the junction cavity, are discussed.