Freiburg 2019 – wissenschaftliches Programm
FM 59.5: Talk
Mittwoch, 25. September 2019, 15:00–15:15, 3043
Towards semiconductor-superconductor hybrid qubits based on core/shell nanowires — •Patrick Zellekens1,2, Russell Deacon3,4, Pujitha Perla1,2, Steffen Schlör5, Mihail Ion Lepsa1,2, Martin Weides5, Koji Ishibashi3,4, Detlev Grützmacher1,2, and Thomas Schäpers1,2 — 1Peter Grünberg Institute, Forschungszentrum Jülich, 52428 Jülich, Germany — 2JARA-FIT, Fundamentals of Future Information Technology — 3RIKEN Center for Emergent Matter Science, 351-0198 Saitama, Japan — 4Advanced Device Laboratory, RIKEN, 351-0198 Saitama, Japan — 5Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
State-of-the-art qubits are typically tuned in frequency by a magnetic field. Our goal is to fabricate and characterize electrically tunable qubits, i.e. Gatemon and Andreev qubits, using a semiconductor nanowire Josephson junction as nonlinear element.
The main limitation for the qubit performance is the semiconductor-superconductor interface. We present a detailed analysis of the DC- and AC-properties of InAs/Al and InAs/Nb nanowire Josephson junctions with epitaxially grown superconductor shells based on Shapiro, emission and gate-dependent VI measurements.
Additionally, we present flux- and gate-dependent measurements of Andreev qubits as well as the spectroscopy of individual Andreev bound states by means of pump-probe experiments. The latter one reveals a Rashba- induced lifting of the spin degeneracy, which is one of the prerequisites for the realization of Majorana fermions.