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arXiv · 1703.06996

Modeling Bloch Oscillations in Nanoscale Josephson Junctions

Heli Vora·R. L. Kautz·S. W. Nam·J. Aumentado
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Abstract

Bloch oscillations in nanoscale Josephson junctions with a Coulomb charging energy comparable to the Josephson coupling energy are explored within the context of a model previously considered by Geigenm\"uller and Sch\"on that includes Zener tunneling and treats quasiparticle tunneling as an explicit shot-noise process. The dynamics of the junction quasicharge are investigated numerically using both Monte Carlo and ensemble approaches to calculate voltage--current characteristics in the presence of microwaves. We examine in detail the origin of harmonic and subharmonic Bloch steps at dc biases $I=(n/m)2ef$ induced by microwaves of frequency $f$ and consider the optimum parameters for the observation of harmonic ($m=1$) steps. We also demonstrate that the GS model allows a detailed semi-quantitative fit to experimental voltage--current characteristics previously obtained at the Chalmers University of Technology, confirming and strengthening the interpretation of the observed microwave-induced steps in terms of Bloch oscillations.

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Heli Vora, R. L. Kautz, S. W. Nam, J. Aumentado. 2017-03-20. Modeling Bloch Oscillations in Nanoscale Josephson Junctions. https://doi.org/10.1103/physrevb.96.054505

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