We have found that crystalline Josephson junctions have critical current density control problems which decrease circuit yield. We present a qubit circuit designed to accommodate a factor-of-five variation in critical current density for the evaluation of advanced tunnel barrier materials for Josephson phase qubits. Using this circuit design, we compare the performance of qubits fabricated with MgO and Al2O3 advanced crystalline tunnel barriers to AlOx amorphous tunnel barrier qubits.
Citation: Superconductor Science & Technology
Pub Type: Journals