Current-voltage characteristics of tunnel Josephson junctions with a ferromagnetic interlayer
Current-voltage characteristics of tunnel Josephson junctions with a ferromagnetic interlayer
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具有铁磁夹层的隧道约瑟夫森结的电流-电压特性
DOI：
10.1103/physrevb.84.024524
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
and F. W. J. Hekking
中科院分区：
文献类型：
--
作者：
S. Vasenko;S. Kawabata;A. A. Golubov;M. Yu. Kupriyanov;C. Lacroix;F. S. Bergeret;and F. W. J. Hekking
本文对扩散超导体/绝缘体/铁磁体/超导体（SIFS）隧道约瑟夫森结的电流-电压特性（CVC）进行了定量研究。为了获得CVC，我们计算的状态密度（DOS）的F/S双层任意长度的铁磁层，使用准经典理论。当铁磁层厚度大于超导凝聚体进入F层的特征穿透深度时，我们找到了一个与用自洽数值方法得到的DOS一致的解析表达式。我们讨论了DOS的一般性质及其对铁磁层参数的依赖性。特别是我们集中我们的分析在费米能量的DOS振荡。使用数值得到的DOS，我们计算相应的CVC，并讨论其性质。最后，我们使用CVC计算宏观量子隧穿（MQT）逃逸率的电流偏置SIFS结考虑到耗散修正由于准粒子隧穿。我们发现准粒子耗散对SIFS结宏观量子动力学的影响很小，这是SIFS结在超导量子比特应用中的一个优势。
We present a quantitative study of the current-voltage characteristics (CVC) of diffusive superconductor/insulator/ferromagnet/superconductor (SIFS) tunnel Josephson junctions. In order to obtain the CVC we calculate the density of states (DOS) in the F/S bilayer for arbitrary length of the ferromagnetic layer, using quasiclassical theory. For a ferromagnetic layer thickness larger than the characteristic penetration depth of the superconducting condensate into the F layer, we find an analytical expression which agrees with the DOS obtained from a self-consistent numerical method. We discuss general properties of the DOS and its dependence on the parameters of the ferromagnetic layer. In particular we focus our analysis on the DOS oscillations at the Fermi energy. Using the numerically obtained DOS we calculate the corresponding CVC and discuss their properties. Finally, we use CVC to calculate the macroscopic quantum tunneling (MQT) escape rate for the current biased SIFS junctions by taking into account the dissipative correction due to the quasiparticle tunneling. We show that the influence of the quasiparticle dissipation on the macroscopic quantum dynamics of SIFS junctions is small, which is an advantage of SIFS junctions for superconducting qubits applications.