Berlin 2015 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 24: Focus Session: Functional Semiconductor Nanowires II (organized by HL)

TT 24.9: Vortrag

Montag, 16. März 2015, 17:45–18:00, EW 201

Giant Magnetoconductance Oscillations in Hybrid Superconductor - Semiconductor Core/Shell Nanowire Devices — •Fabian Haas^1,2, Önder Gül^1,2, Haci Yusuf Günel^1,2, Hans Lüth^1,2, Torsten Rieger^1,2, Tobias Wenz^1,2, Patrick Zellekens^1,2, Mihail Lepsa^1,2, Gregory Panaitov^1,2, Detlev Grützmacher^1,2, and Thomas Schäpers^1,2 — ¹Peter Grünberg Institute (PGI-9 and PGI-8), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany — ²JARA - Fundamentals of Future Information Technology

In GaAs/InAs core/shell nanowires the electrons are confined in the cylindrical conductive InAs shell. In recent publications we have shown that this InAs nanotube allows the observation of h/e flux periodic oscillations in the nanowires magnetoconductance, when a magnetic field is aligned in parallel with the nanowire axis.

In this contribution, we present novel magnetotransport measurements of GaAs/InAs core/shell nanowires, this time contacted with two superconducting Nb electrodes. We observe regular h/2e half-flux periodic oscillations with amplitudes in the order of e²/h, which is larger by two orders of magnitude than observed for the h/e oscillations in a reference sample contacted with Ti/Au leads.

Phase-coherent resonant Andreev reflections at the Nb-nanowire interface, where interfering electron-hole trajectories enclose the penetrating magnetic flux, can explain these strongly enhanced oscillations as well as the h/2e flux periodicity.