Rapid single-flux quantum logic using π-shifters

作者：Alexey Vladimirovich Ustinov, V. K. Kaplunenko · 发表于：Journal of Applied Physics · 年份：2003 · DOI：10.1063/1.1604964 · 被引用次数：133 · 研究领域：Physics of Superconductivity and Magnetism、Quantum and electron transport phenomena、Magnetic and transport properties of perovskites and related materials

We have found that the size of some rapid single-flux quantum (RSFQ) logic cells based on conventional 0-type Josephson junctions can be significantly reduced by using a π-type junction as a phase shifter in passive (nonswitching) mode. In comparison with the recently suggested active (switching) π-junctions mode, the passive mode offers much greater operation margins for their critical current Icπ. This gives π-junctions a chance to be implemented in RSFQ designs in the near future. As an example, we have simulated the operation of a toggle flip flop with zero-geometrical inductance of the fluxon storage loop. Simulations show that the parametric inductance of the π-junction and its normal resistance Rn form a low-pass filter, which sets the low limit for π-junctions IcπRn product, but offers a wide range of variations of the other parameters. The possible reduction of RSFQ cell size by using π-junctions opens the way to scale superconducting logic circuits down to the submicron dimensions.