Josephson junction dynamics in the presence of $2\pi$- and $4\pi$-periodic supercurrents

Abstract : We investigate theoretically the dynamics of a Josephson junction in the framework of the RSJ model. We consider a junction that hosts two supercurrrent contributions: a $2\pi$- and a $4\pi$-periodic in phase, with intensities $I_{2\pi}$ and $I_{4\pi}$ respectively. We study the size of the Shapiro steps as a function of the ratio of the intensity of the mentioned contributions, i.e. $I_{4\pi}/I_{2\pi}$. We provide detailed explanations where to expect clear signatures of the presence of the $4\pi$-periodic contribution as a function of the external parameters: the intensity AC-bias $I_\text{ac}$ and frequency $\omega_\text{ac}$. On the one hand, in the low AC-intensity regime (where $I_\text{ac}$ is much smaller than the critical current, $I_\text{c}$), we find that the non-linear dynamics of the junction allows the observation of only even Shapiro steps even in the unfavorable situation where $I_{4\pi}/I_{2\pi}\ll 1$. On the other hand, in the opposite limit ($I_\text{ac}\gg I_\text{c}$), even and odd Shapiro steps are present. Nevertheless, even in this regime, we find signatures of the $4\pi$-supercurrent in the beating pattern of the even step sizes as a function of $I_\text{ac}$.
Type de document :
Article dans une revue
Physical Review B : Condensed matter and materials physics, American Physical Society, 2017, 95 (19), pp.195430. 〈10.1103/PhysRevB.95.195430〉
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http://hal.upmc.fr/hal-01540470
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Soumis le : vendredi 16 juin 2017 - 13:07:33
Dernière modification le : jeudi 25 janvier 2018 - 11:42:02

Citation

F. Domínguez, O. Kashuba, E. Bocquillon, J. Wiedenmann, R. S. Deacon, et al.. Josephson junction dynamics in the presence of $2\pi$- and $4\pi$-periodic supercurrents. Physical Review B : Condensed matter and materials physics, American Physical Society, 2017, 95 (19), pp.195430. 〈10.1103/PhysRevB.95.195430〉. 〈hal-01540470〉

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