Josephson结与谐振腔耦合的数值研究

STUDY OF CAVITYCOUPLED JOSEPHSON DEVICE USING NUMERICAL METHOD

根据谐振腔与Ｊｏｓｅｐｈｓｏｎ结耦合结构的等效电路模型，用数值计算方法研究了结与谐振腔互作用时的Ｊｏｓｅｐｈｓｏｎ效应，得出了腔感应电流台阶高度与谐振电路的品质因素Ｑ值之间的关系；在外加微波辐照下，发现Ｓｈａｐｉｒｏ台阶高度随微波功率的变化规律也有变化，并计算了损耗电阻ＲＬ对耦合结构Ｓｈａｐｉｒｏ台阶高度随微波功率变化关系的影响．基于以上关系，我们提出了利用腔结耦合测量超导薄膜表面电阻的初步设想．

The Circuit model of the Cavitycoupled Josephson junction is studied using numerical methods. The relationship between the Cavity-induced current steps and the unloaded Q value of the resonance circuit has been achieved. When external microwave radiation is present, the dependence of the height of Shapiro steps on both the loss resistance RL and the microwave power has been also obtained. And it shows that the heights of Shapiro steps sensitively depend on the RL of the resonance circuit under some radiation levels. Thus,a new tentative idea is presented to measure the surface resistance of superconductive thin films which are some parts of the resonator. 