Reconfigurable adiabatic quantum-flux-parametron with superconducting phase shift controlled by magnetic flux
Aoto Tanaoka, Nobuyuki Yoshikawa, Yuki Yamanashi
Abstract The adiabatic quantum-flux-parametron (AQFP), which can operate with ultra-low energy consumption, has attracted attention as an alternative to semiconductor circuits. The development of reconfigurable AQFP devices is essential for advancing AQFP integrated circuits. However, research on reconfigurable devices at the logic gate level remains limited. We propose an AQFP circuit capable of reconfiguring its logic function by controlling the superconducting phase shift through externally applied magnetic flux. In AQFP logic, logic ‘1’ and ‘0’ are represented by the polarity of the current. The proposed circuit can switch between the Buffer function, which propagates the input current with its polarity unchanged, and the NOT function, which propagates it with the polarity inverted. We analytically derived the parameter conditions for correct operation and determined the parameters within this range to achieve adiabatic operation and sufficient element margins for experimental demonstration. We fabricated the proposed reconfigurable circuit using the 10 kA cm −2 Nb four-layer superconducting circuit fabrication process, and experimentally confirmed correct operation for both the Buffer and NOT functions. The control current margins, which are responsible for the functional reconfiguration, were −2.3% to +31.2% for chip 1 and +0.8% to +35.1% for chip 2. Both margins had widths comparable to the simulation result. This work presents the first experimental demonstration of an AQFP circuit whose function can be reconfigured using only a control current. We believe this work will contribute to the advancement of reconfigurable AQFP devices.
Superconductor Science and Technology•Jul 1, 2026•0 citations