Berlin 2018 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 4: Superconductivity: Qubits I
TT 4.5: Vortrag
Montag, 12. März 2018, 10:30–10:45, H 2053
Transmon qubit circuits based on semiconductor/superconductor core/shell nanowire Josephson junctions — •Patrick Zellekens1,2, Steffen Schlör3, Tobias Ziegler1,2, Nicolas Güsken1,2, Torsten Rieger1,2, Benjamin Bennemann1,2, Mihail Ion Lepsa1,2, Detlev Grützmacher1,2, Martin Weides3, and Thomas Schäpers1,2 — 1Peter Gruenberg Institute 9, Forschungszentrum Juelich, 52425 Juelich, Germany — 2JARA - Fundamentals of Future Information Technologies — 3Physikalisches Institut, Karlsruher Institut für Technologie
State-of-the-art qubits, like the transmon, are typically tuned in frequency by a magnetic field. Our goal is to fabricate and characterize an electrically tunable qubit in the GHz regime, using a semiconductor nanowire Josephson junction as nonlinear element. Thereby it is possible to tune the resonance frequency of the qubit without a magnetic flux bias. The main limitation for the qubit performance is the semiconductor-superconductor interface as well as the coherence properties of the surrounding circuit. In order to address this issue and to optimize the interface properties, an in-situ fabrication approach was chosen, in which the nanowire is directly covered with a superconducting shell. Subsequently, Josephson junctions are fabricated and electrically characterized at low temperature. Finally, implementations as building blocks for 2-dimensional transmon qubits based on TiN will be shown.