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Reflectionless tunneling in planar Nb/GaAs hybrid junctions

Francesco Giazotto·Marco Cecchini·Pasqualantonio Pingue·Fabio Beltram·Marco Lazzarino·Daniela Orani·Silvia Rubini·Alfonso Franciosi
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Abstract

Reflectionless-tunneling was observed in Nb/GaAs superconductor/semiconductor junctions fabricated through a two-step procedure. First, periodic $δ$-doped layers were grown by molecular beam epitaxy near the GaAs surface, followed by an As cap layer to protect the surface during {\it ex-situ} transfer. Second, Nb was deposited by dc-magnetron sputtering onto the GaAs(001) 2 $\times$ 4 surface {\it in-situ} after thermal desorption of the cap layer. The magnetotransport behavior of the resulting hybrid junctions was successfully analyzed within the random matrix theory of phase-coherent Andreev transport. The impact of junction morphology on reflectionless tunneling and the applicability of the fabrication technique to the realization of complex superconductor/semiconductor mesoscopic systems are discussed.

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Francesco Giazotto, Marco Cecchini, Pasqualantonio Pingue, Fabio Beltram, Marco Lazzarino, Daniela Orani, Silvia Rubini, Alfonso Franciosi. 2001-02-03. Reflectionless tunneling in planar Nb/GaAs hybrid junctions. https://doi.org/10.1063/1.1357211

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