Dynamics of Josephson junctions and single-flux-quantum networks with superconductor–insulator–normal-metal junction shunts

Within the framework of the microscopic model of tunneling, we modeled the behavior of the Josephson junction shunted by the superconductor--insulator--normal-metal (SIN) tunnel junction. The electromagnetic impedance of the SIN junction includes both the frequency-dependent damping and reactance, which affect the circuit dynamics. We calculated the dc I-V curves and transient characteristics and show their differences to the characteristics obtained within the simpler models. The correct operation of the basic single-flux-quantum circuits, i.e., the Josephson transmission line and the toggle flip-flop, based on such SIN-shunted Josephson junctions with small damping at low frequencies, has also been modeled.