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arXiv · 1506.04597

High Efficiency CVD Graphene-lead (Pb) Cooper Pair Splitter

I. V. Borzenets·Y. Shimazaki·G. F. Jones·M. F. Craciun·S. Russo·Y. Yamamoto·S. Tarucha
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Abstract

We demonstrate high efficiency Cooper pair splitting in a graphene-based device. We utilize a true Y-shape design effectively placing the splitting channels closer together: graphene is used as the central superconducting electrode as well as QD output channels, unlike previous designs where a conventional superconductor was used with tunnel barriers to the quantum dots (QD) of a different material. Superconductivity in graphene is induced via the proximity effect, thus resulting in both a large measured superconducting gap $\Delta=0.5$meV, and a long coherence length $\xi=200$nm. The graphene-graphene, flat, two dimensional, superconductor-QD interface lowers the capacitance of the quantum dots, thus increasing the charging energy $E_C$ (in contrast to previous devices). As a result we measure a visibility of up to 96% and a splitting efficiency of up to 62%. Finally, the devices utilize graphene grown by chemical vapor deposition allowing for a standardized device design with potential for increased complexity.

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I. V. Borzenets, Y. Shimazaki, G. F. Jones, M. F. Craciun, S. Russo, Y. Yamamoto, S. Tarucha. 2015-06-15. High Efficiency CVD Graphene-lead (Pb) Cooper Pair Splitter. https://arxiv.org/abs/1506.04597

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