Superconducting Junction of a Single-Crystalline Au Nanowire for an Ideal Josephson Device

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• 作者：Minkyung Jung ; Hyunho Noh ; Yong-Joo Doh ; Woon Song ; Yonuk Chong ; Mahn-Soo Choi ; Youngdong Yoo ; Kwanyong Seo ; Nam Kim ; Byung-Chill Woo ; Bongsoo Kim ; Jinhee Kim
• 刊名：ACS Nano
• 出版年：2011
• 出版时间：March 22, 2011
• 年：2011
• 卷：5
• 期：3
• 页码：2271-2276
• 全文大小：789K
• 年卷期：0
• ISSN：1936-086X

文摘

We report on the fabrication and measurements of a superconducting junction of a single-crystalline Au nanowire, connected to Al electrodes. The current−voltage characteristic curve shows a clear supercurrent branch below the superconducting transition temperature of Al and quantized voltage plateaus on application of microwave radiation, as expected from Josephson relations. Highly transparent (0.95) contacts very close to an ideal limit of 1 are formed at the interface between the normal metal (Au) and the superconductor (Al). The very high transparency is ascribed to the single crystallinity of a Au nanowire and the formation of an oxide-free contact between Au and Al. The subgap structures of the differential conductance are well explained by coherent multiple Andreev reflections (MAR), the hallmark of mesoscopic Josephson junctions. These observations demonstrate that single crystalline Au nanowires can be employed to develop novel quantum devices utilizing coherent electrical transport.