Design and characterization of adiabatic quantum flux parametron using sub-<i>μ</i>m cross-type Josephson junction technology

Abstract We report on the design and implementation of adiabatic quantum flux parametron (AQFP) buffer gates utilizing cross-type Nb/AlO x /Nb Josephson junctions with I C of 20 μ A, designed to operate at mK temperatures. We, therefore, discuss design considerations, circuit simulation and optimization and their technological implementation. The preliminary results of the test circuit at 4.2 K are demonstrated focusing on the performance. Particularly, we emphasize on the current sensitivity of the circuit based on the output switching probability. The measurement results, show a narrow grayzone width of 0.48 μ A for low-speed operation, demonstrating a higher current sensitivity. Additionally, the designed AQFP circuit exhibits a wide operating margins, further endorsing their potential for high sensitivity based superconducting sensors and scalable interface circuits for quantum electronics.