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

TY - JOUR

T1 - Proximity Effect Transfer from NbTi into a Semiconductor Heterostructure via Epitaxial Aluminum

AU - Drachmann, A C C

AU - Suominen, H J

AU - Kjærgaard, Morten

AU - Shojaei, B

AU - Palmstrøm, C J

AU - Marcus, C M

AU - Nichele, F

N1 - [Qdev]

PY - 2017/2/8

Y1 - 2017/2/8

N2 - 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.

AB - 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.

KW - Journal Article

U2 - 10.1021/acs.nanolett.6b04964

DO - 10.1021/acs.nanolett.6b04964

M3 - Journal article

C2 - 28072541

SN - 1530-6984

VL - 17

SP - 1200

EP - 1203

JO - Nano Letters

JF - Nano Letters

IS - 2

ER -