论文标题
平面约瑟夫森连接和鱿鱼中相动态的测量
Measurements of Phase Dynamics in Planar Josephson Junctions and SQUIDs
论文作者
论文摘要
我们通过实验研究了平面约瑟夫森连接（JJS）的随机相动态和超导量子干扰装置（Squid）在外观INAS/AL异质结构中定义的，其特征在于Josephson能量与充电能量的较高比率。我们观察到从宏观量子隧穿的制度到相位扩散作为温度的函数的一个交叉，其中过渡温度$ t^{*} $是栅极可调的。开关概率分布显示与小的分流电容和中等阻尼相一致，从而导致开关电流，这是临界电流的一小部分。两个JJ之间的相位锁定导致在隔离测量的JJ和在非对称鱿鱼环中测得的相同JJ的JJ之间的切换电流差异。在循环的情况下，$ t^*$也通过磁通量调节。
We experimentally investigate the stochastic phase dynamics of planar Josephson junctions (JJs) and superconducting quantum interference devices (SQUIDs) defined in epitaxial InAs/Al heterostructures, and characterized by a large ratio of Josephson energy to charging energy. We observe a crossover from a regime of macroscopic quantum tunneling to one of phase diffusion as a function of temperature, where the transition temperature $T^{*}$ is gate-tunable. The switching probability distributions are shown to be consistent with a small shunt capacitance and moderate damping, resulting in a switching current which is a small fraction of the critical current. Phase locking between two JJs leads to a difference in switching current between that of a JJ measured in isolation and that of the same JJ measured in an asymmetric SQUID loop. In the case of the loop, $T^*$ is also tuned by a magnetic flux.
