Superfluid flow in disordered superconductors with Dynes pair-breaking scattering: Depairing current, kinetic inductance, and superheating field
Superfluid flow in disordered superconductors with Dynes pair-breaking scattering: Depairing current, kinetic inductance, and superheating field
复制标题
DOI：
10.1103/physrevresearch.2.033203
复制
发表时间：
2020-04
影响因子：
4.2
通讯作者：
Takayuki Kubo
中科院分区：
文献类型：
--
作者：
Takayuki Kubo
我们通过在所有温度 $T$、所有 $\Gamma$ 和所有超流体动量的扩散极限下自洽求解 BCS 理论的耦合麦克斯韦和 Usadel 方程，研究了达因破偶散射率 $\Gamma$ 对窄薄膜超导体和半无限超导体中超流体流动的影响。考虑到非线性迈斯纳效应，我们获得了窄薄膜中的脱对电流密度 $j_d(\Gamma, T)$ 和与电流相关的非线性运动电感 $L_k(j_s, \Gamma, T)$ 以及半无限超导体中的过热场 $H_{sh}(\Gamma, T)$ 和电流分布。还导出了$j_d(\Gamma,T)|_{T=0}$、$L_k(j_s,\Gamma,T)|_{T=0}$和$H_{sh}(\Gamma,T)|_{T=0}$的解析表达式。该理论表明$j_d$和$H_{sh}$可以通过减少$\Gamma$来改善，$L_k$可以通过偏置电流和$\Gamma$的组合来调整。隧道光谱可以测试该理论，还可以深入了解如何通过材料加工来设计 $\Gamma$。该理论的含义将有助于提高各种超导量子器件的性能。
We investigate the effects of Dynes pair-breaking scattering rate $\Gamma$ on the superfluid flow in a narrow thin-film superconductor and a semi-infinite superconductor by self-consistently solving the coupled Maxwell and Usadel equations for the BCS theory in the diffusive limit for all temperature $T$, all $\Gamma$, and all superfluid momentum. We obtain the depairing current density $j_d(\Gamma, T)$ and the current-dependent nonlinear kinetic inductance $L_k(j_s, \Gamma, T)$ in a narrow thin-film and the superheating field $H_{sh}(\Gamma, T)$ and the current distribution in a semi-infinite superconductor, taking the nonlinear Meissner effect into account. The analytical expressions for $j_d(\Gamma,T)|_{T=0}$, $L_k(j_s, \Gamma, T)|_{T=0}$, and $H_{sh}(\Gamma, T)|_{T=0}$ are also derived. The theory suggests $j_d$ and $H_{sh}$ can be ameliorated by reducing $\Gamma$, and $L_k$ can be tuned by a combination of the bias current and $\Gamma$. Tunneling spectroscopy can test the theory and also give insight into how to engineer $\Gamma$ via materials processing. Implications of the theory would be useful to improve performances of various superconducting quantum devices.