Critical Current Scaling in Long Diffusive Graphene-Based Josephson Junctions

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• 作者：Chung Ting Ke ; Ivan V. Borzenets ; Anne W. Draelos ; Francois Amet ; Yuriy Bomze ; Gareth Jones ; Monica Craciun ; Saverio Russo ; Michihisa Yamamoto ; Seigo Tarucha ; Gleb Finkelstein
• 刊名：Nano Letters
• 出版年：2016
• 出版时间：August 10, 2016
• 年：2016
• 卷：16
• 期：8
• 页码：4788-4791
• 全文大小：327K
• 年卷期：0
• ISSN：1530-6992

文摘

We present transport measurements on long, diffusive, graphene-based Josephson junctions. Several junctions are made on a single-domain crystal of CVD graphene and feature the same contact width of ∼9 μm but vary in length from 400 to 1000 nm. As the carrier density is tuned with the gate voltage, the critical current in these junctions ranges from a few nanoamperes up to more than 5 μA, while the Thouless energy, E_Th, covers almost 2 orders of magnitude. Over much of this range, the product of the critical current and the normal resistance I_CR_N is found to scale linearly with E_Th, as expected from theory. However, the value of the ratio I_CR_N/E_Th is found to be 0.1–0.2, which much smaller than the predicted ∼10 for long diffusive SNS junctions.