Flip-Chip-Based Microwave Spectroscopy of Andreev Bound States in a Planar Josephson Junction
Manuel Hinderling, Deividas Sabonis, Stephan Paredes, D. Z. Haxell, Marco Coraiola, Sofieke C. ten Kate, Erik Cheah, F. Krizek, Rüdiger Schott, W. Wegscheider, Fabrizio Nichele
Abstract
Measurement and coherent manipulation of Andreev bound states (ABSs) in planar superconductor-semiconductor heterostructures could enable gate-controllable, small-footprint superconducting spin qubits with long coherence times. So far, readout capabilities and device coherence have been limited by lossy $I\phantom{\rule{0}{0ex}}I\phantom{\rule{0}{0ex}}I\ensuremath{-}V$ substrates, but here researchers overcome this limitation with a flip-chip approach to microwave experiments on ABSs. Superconductor-semiconductor devices and microwave resonators are placed on different chips and inductively coupled via a vacuum gap, enabling high-quality readout without sacrificing device properties.