[16p-D215-1~16] 11.5 Junction and circuit fabrication process, digital applications

▲ [16p-D215-3] Superconducting Diode Using π-JJ-based Arbitrary Phase Shifter

〇Feng Li¹, Taichi Sato¹, Hinata Fujisawa¹, Yuto Takeshita¹, Masamitsu Tanaka¹, Akira Fujimaki¹ (1.Nagoya Univ.)

Keywords:superconductor, diode, Josephson junction

Ferromagnetic π phase Josephson junction (JJ) has been adopted as negative π phase shifter into superconducting digital [1] and quantum circuits [2]. To realize arbitrary phase shifter, a flux trapped superconducting loop has been adopted. By controlling the contact ports, partial of the trapped flux can be coupled into the target device or circuit, however, the number of flux quantum trapped in the superconducting loop is not easy to control [3].
Here we proposed a practical arbitrary phase shifter with a π-JJ RF SQUID, in which half-flux-quantum is stored. By adjusting the contact ports to the proposed RF SQUID, arbitrary phase shifter between 0 to π can be achieved. Note that arbitrary phase shift between π to 2π can also be realized if an additional π-JJ is connected to the RF SQUID in series. We adopt a π/2 phase shifter into an unsymmetric DC SQUID to construct a superconducting diode. Without external magnetic field, our superconducting diode shows unsymmetric I-V curve (I_c+ /I_c- ~ 0.4) and the modulation pattern can be fitted with theoretical calculation.