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Proximity Effect Transfer from NbTi into a Semiconductor Heterostructure via Epitaxial Aluminum

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A C C Drachmann, H J Suominen, Morten Kjærgaard, B Shojaei, C J Palmstrøm, C M Marcus, F Nichele

We demonstrate the transfer of the superconducting properties of NbTi, a large-gap high-critical-field superconductor, into an InAs heterostructure via a thin intermediate layer of epitaxial Al. Two device geometries, a Josephson junction and a gate-defined quantum point contact, are used to characterize interface transparency and the two-step proximity effect. In the Josephson junction, multiple Andreev reflections reveal near-unity transparency with an induced gap Δ* = 0.50 meV and a critical temperature of 7.8 K. Tunneling spectroscopy yields a hard induced gap in the InAs adjacent to the superconductor of Δ* = 0.43 meV with substructure characteristic of both Al and NbTi.

Original languageEnglish
JournalNano Letters
Issue number2
Pages (from-to)1200-1203
Number of pages4
StatePublished - 8 Feb 2017

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  • Journal Article

ID: 180970006