Dynamics of first and second switches in Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ intrinsic Josephson junctions stacks measured by specific designed electronics
Dynamics of first and second switches in Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ intrinsic Josephson junctions stacks measured by specific designed electronics
复制标题
通过特定设计的电子器件测量 Bi$_2$Sr$_2$CaCu$_2$O$_{8 δ}$ 固有约瑟夫森结堆栈中第一和第二开关的动态
DOI：
10.1109/tasc.2016.2642043
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发表时间：
2017
影响因子：
1.8
通讯作者：
and I. Kakeya
中科院分区：
文献类型：
--
作者：
Y. Nomura;R. Okamoto;and I. Kakeya
我们测量了Bi2Sr2CaCu2O8+δ本征约瑟夫森结堆叠的第一和第二开关的开关概率分布。为了测量开关概率分布，我们设计了一个电流源，并引入了微控制器。分辨率和精度足以测量本征约瑟夫逊结的开关概率分布。对于第一个开关，热激活逸出和宏观量子隧穿之间的交叉温度在0.8 ~ 2.2 K之间。对于临界密度为1.0和2.0 kA/cm2的样品，第二个开关的交叉温度分别约为8.0和6.8 K。我们分析了临界电流密度与第二开关交叉温度的关系。交叉温度随临界电流密度的增加而降低。这种反相关既不能用单结模型解释，也不能用加热效应解释。反相关是在二次开关中观察到的一种特殊现象。我们认为反相关是由电容耦合引起的。随着载流子密度的增加，电荷屏蔽长度变短，使得临界电流密度越高的ijs电容耦合强度越弱。
We measure switching probability distributions for the first and the second switches of stacks of Bi2Sr2CaCu2O8+δintrinsic Josephson junctions. To measure switching probability distributions, we design a current source and introduced a microcontroller. The resolution and accuracy are sufficient for measuring switching probability distributions of intrinsic Josephson junctions. For the first switch, crossover temperatures between thermally activated escape and macroscopic quantum tunneling are in the range between 0.8 and 2.2 K. The crossover temperatures of the second switch are approximately 8.0 and 6.8 K for the samples with critical densities of 1.0 and 2.0 kA/cm2, respectively. We analyze critical current density dependence of the crossover temperature of the second switch. The crossover temperature decreases with increasing critical current density. This anticorrelation can be explained neither by the single-junction model nor by the heating effect. The anticorrelation is a peculiar phenomenon observed in the second switch. We consider that the anticorrelation is attributed to the capacitive coupling. The strength of the capacitive coupling is weaker in IJJs with higher critical current density because the charge screening length is shorter due to increase of carrier density.