Macroscopic quantum tunneling and phase diffusion in a La<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mrow><mml:mn>2</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi></mml:mrow></mml:msub></mml:math>Sr<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mi>x</mml:mi></mml:msub></mml:math>CuO<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mn>4</mml:mn></mml:

Kubo, Yuimaru; Sboychakov, A. O.; Nori, Franco; Yamaguchi, Takahide; Ueda, Shigenori; Tanaka, Isao; Islam, A. T. M. N.; Takano, Yoshihiko

doi:10.1103/physrevb.86.144532

Cited by 9 publications

(4 citation statements)

References 47 publications

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“…In a large junction where the length of the junction L is considerably larger than the Josephson penetration depth l J , current density is not uniform over the junction because of the shielding effect. As a result, the height of the effective potential barrier is reduced by a factor of l L J because of the self-field induced by the bias current [41,42]. This effect adds a constant factor to T eff , which is determined by l L J , and ends in an upward parallel shift in a log-log plot of T eff versus T bath .…”

Section: Experiments and Data Analysismentioning

confidence: 99%

Negative correlation between enhanced crossover temperature and fluctuation-free critical current of the second switch in Bi₂Sr₂CaCu₂O${}_{8+\delta }$ intrinsic Josephson junction

Nomura

Okamoto

Kakeya

2017

Supercond. Sci. Technol.

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We have investigated the switching dynamics of the first and second switches in intrinsic Josephson junctions (IJJs) of Bi2Sr2CaCu2O with different maximum Josephson current density Jc to reveal the doping evolution of interaction between IJJs. For the second switch, the crossover temperature between temperature-independent switching similar to quantum tunneling and thermally activated switching is remarkably higher than that for the first switch. Moreover, slightly decreases with increasing Jc, which violates the conventional relation between the crossover temperature and the critical current density. These features can be explained not by a change in the Josephson coupling energy but by a change in the charging energy of the Josephson junction. We argue that the capacitive coupling model explains the increase in the fluctuation in the quantum regime of the second switch and the anti-correlation between and Jc. Furthermore, inductive coupling does not contribute to these peculiar phenomena in the switching dynamics of stacked IJJs.

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Section: Experiments and Data Analysismentioning

confidence: 99%

Negative correlation between enhanced crossover temperature and fluctuation-free critical current of the second switch in Bi₂Sr₂CaCu₂O${}_{8+\delta }$ intrinsic Josephson junction

Nomura

Okamoto

Kakeya

2017

Supercond. Sci. Technol.

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“…Recently the theory has been further extended and found to describe excellently the phase diffusion (PD) phenomena in the La 2−x Sr x CuO 4 IJJ stacks [23].…”

Section: Introductionmentioning

confidence: 99%

Resonant phase escape in Bi₂Sr₂CaCu₂O_8+δsurface intrinsic Josephson junctions

Zhu

Ren

et al. 2013

New J. Phys.

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We present a study of phase escape in surface Bi 2 Sr 2 CaCu 2 O 8+δ intrinsic Josephson junctions in the presence of microwave radiation. The measured switching current distributions display clear double-peak structures in the microwave field, which result from the single-and two-photon resonant escape processes accompanied by microwave-induced potential barrier suppression. We show that these results can be well explained by a quantummechanical model proposed by Fistul et al (2003 Phys. Rev . B 68 060504), from which the power and frequency dependences of the switching current distributions can be reproduced.

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“…It is well known that at low temperatures switching from the superconducting (the zero-voltage) state to a resistive one occurs in the form of macroscopic quantum tunneling (MQT) of a Josephson phase [1,3,4,[6][7][8][9]. At high temperatures the so-called Josephson phase escape phenomenon is determined by thermal fluctuations.…”

Section: Introductionmentioning

confidence: 99%

“…Currently there is a great interest in experimental and theoretical studies of macroscopic quantum phenomena in diverse Josephson systems [1][2][3][4][5][6][7][8][9]. It is well known that at low temperatures switching from the superconducting (the zero-voltage) state to a resistive one occurs in the form of macroscopic quantum tunneling (MQT) of a Josephson phase [1,3,4,[6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Resonant enhancement of macroscopic quantum tunneling in Josephson junctions: Influence of coherent two-level systems

Fistul¹

2015

Phys. Rev. B

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We report a theoretical study of the macroscopic quantum tunneling (MQT) in small Josephson junctions containing randomly distributed two-level systems. We focus on a Josephson phase escape for switching from the superconducting (the zero-voltage) state to a resistive one. Above the crossover temperature T cr the thermal fluctuations of the Josephson phase induce such a switching, and as T < T cr the regime of the MQT occurs. In the absence of two-level systems (TLSs) a magnetic field applied parallel to the junction plane results in a smooth reduction of T cr ( ), where is an applied magnetic flux. As the TLSs are present in Josephson junctions we obtain a resonant enhancement of the MQT. This phenomenon manifests itself by a narrow peak in the dependence of T cr ( ) occurring in the intermediate range of , i.e., 0 < < φ 0 (φ 0 is the magnetic flux quantum). We explain this effect quantitatively by a strong resonant suppression of the potential barrier for the Josephson phase escape that is due to the coherent quantum Rabi oscillations in two-level systems present in the junction.

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Macroscopic quantum tunneling and phase diffusion in a La2−xSrxCuO4

Cited by 9 publications

References 47 publications

Negative correlation between enhanced crossover temperature and fluctuation-free critical current of the second switch in Bi₂Sr₂CaCu₂O${}_{8+\delta }$ intrinsic Josephson junction

Negative correlation between enhanced crossover temperature and fluctuation-free critical current of the second switch in Bi₂Sr₂CaCu₂O${}_{8+\delta }$ intrinsic Josephson junction

Resonant phase escape in Bi₂Sr₂CaCu₂O_8+δsurface intrinsic Josephson junctions

Resonant enhancement of macroscopic quantum tunneling in Josephson junctions: Influence of coherent two-level systems

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Macroscopic quantum tunneling and phase diffusion in a La2−xSrxCuO4

Cited by 9 publications

References 47 publications

Negative correlation between enhanced crossover temperature and fluctuation-free critical current of the second switch in Bi2Sr2CaCu2O${}_{8+\delta }$ intrinsic Josephson junction

Negative correlation between enhanced crossover temperature and fluctuation-free critical current of the second switch in Bi2Sr2CaCu2O${}_{8+\delta }$ intrinsic Josephson junction

Resonant phase escape in Bi2Sr2CaCu2O8+δsurface intrinsic Josephson junctions

Resonant enhancement of macroscopic quantum tunneling in Josephson junctions: Influence of coherent two-level systems

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Product

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Negative correlation between enhanced crossover temperature and fluctuation-free critical current of the second switch in Bi₂Sr₂CaCu₂O${}_{8+\delta }$ intrinsic Josephson junction

Negative correlation between enhanced crossover temperature and fluctuation-free critical current of the second switch in Bi₂Sr₂CaCu₂O${}_{8+\delta }$ intrinsic Josephson junction

Resonant phase escape in Bi₂Sr₂CaCu₂O_8+δsurface intrinsic Josephson junctions