ORCID Profile
0000-0002-0330-4646
Current Organisation
University of Colorado at Boulder
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Publisher: American Physical Society (APS)
Date: 12-2020
Publisher: AIP Publishing
Date: 12-01-2021
DOI: 10.1063/5.0029855
Abstract: Epitaxially grown superconductor/dielectric/superconductor trilayers have the potential to form high-performance superconducting quantum devices and may even allow scalable superconducting quantum computing with low-surface-area qubits such as the merged-element transmon. In this work, we measure the power-independent loss and two-level-state (TLS) loss of epitaxial, wafer-bonded, and substrate-removed Al/GaAs/Al trilayers by measuring lumped element superconducting microwave resonators at millikelvin temperatures and down to single-photon powers. The power-independent loss of the device is (4.8±0.1)×10−5, and the resonator-induced intrinsic TLS loss is (6.4±0.2)×10−5. Dielectric loss extraction is used to determine a lower bound of the intrinsic TLS loss of the trilayer of 7.2×10−5. The unusually high power-independent loss is attributed to GaAs’s intrinsic piezoelectricity.
Publisher: AIP Publishing
Date: 15-09-2020
DOI: 10.1063/5.0023743
Abstract: Epitaxial Al/GaAs/Al structures having controlled thickness of high-quality GaAs and pristine interfaces have been fabricated using a wafer-bonding technique. III–V semiconductor/Al structures are grown by molecular beam epitaxy on III–V semiconductor substrates and bonded to silicon and sapphire. Selective etching is used to remove the III–V substrate followed by surface cleaning and superconductor regrowth, resulting in epitaxial Al/GaAs/Al tri-layers on sapphire or silicon substrates. Structures are characterized with reflection high energy electron diffraction, atomic force microscopy, x-ray photoelectron spectroscopy, transmission electron microscopy, and x-ray diffraction. Applications of these structures to the field of quantum information processing are discussed.
Publisher: AIP Publishing
Date: 15-03-2021
DOI: 10.1063/5.0048621
Abstract: Due to their unique properties as lossless, nonlinear circuit elements, Josephson junctions lie at the heart of superconducting quantum information processing. Previously, we demonstrated a two-layer, submicrometer-scale overlap junction fabrication process suitable for qubits with long coherence times. Here, we extend the overlap junction fabrication process to micrometer-scale junctions. This allows us to fabricate other superconducting quantum devices. For ex le, we demonstrate an overlap junction-based Josephson parametric lifier that uses only two layers. This efficient fabrication process yields frequency-tunable devices with negligible insertion loss, a gain of ∼30 dB, and quantum limited noise performance. Compared to other processes, the overlap junction allows for fabrication with minimal infrastructure, high yield, and state-of-the-art device performance.
Location: United States of America
No related grants have been discovered for Corey Rae McRae.