论文标题
SuperGAP和子量表增强了不对称{S_1FS_2} Josephson连接
Supergap and subgap enhanced currents in asymmetric {S_1FS_2} Josephson junctions
论文作者
论文摘要
We have theoretically studied the supercurrent profiles in three-dimensional normal metal and ferromagnetic Josephson configurations, where the magnitude of the superconducting gaps in the superconducting leads are unequal, i.e., $Δ_1\neq Δ_2$, creating asymmetric $S_1NS_2$ and $S_1FS_2$ systems.我们的结果表明，通过增加超导差距的比率$Δ_2/δ_1$，弹道$ S_1NS_2 $系统中的关键超电流可以增加$ 100 \％$，并达到饱和点，或者达到饱和点，或者衰减，取决于交界处的厚度，磁性厚度，磁化强度和化学物质。发现扩散的$ S_1NS_2 $系统中的总临界电流被发现增强了$ 50 \％$ $ $ $ $，并通过增加一个超导间隙来达到饱和。在统一的铁磁连接处，超流量通过增加$Δ_2/Δ_1> 1 $来进行逆转。通过将总超电流分解为其超级gap和子隙组件，我们的结果说明了它们对约瑟夫森电流流量的关键相对贡献。发现在$ s_1fs_2 $连接中，子量和超级电流的竞争导致当前相关关系中第二谐波的出现。与扩散的不对称约瑟夫森构型相反，只有$Δ_2/Δ_1= 1 $的超电流的行为只能由Subgap电流组件在包括FERMI水平的范围较大的参数范围内正确地描述，包括FERMI级别级别，磁化强度和连接厚度。有趣的是，当$δ_2/δ_1> 1 $时，我们的结果发现了多个参数集，其中总超恒星由SuperGAP组件驱动。因此，我们的全面研究强调了子gap和超级超级电流组件在弹道和扩散方案中的重要性。
We have theoretically studied the supercurrent profiles in three-dimensional normal metal and ferromagnetic Josephson configurations, where the magnitude of the superconducting gaps in the superconducting leads are unequal, i.e., $Δ_1\neq Δ_2$, creating asymmetric $S_1NS_2$ and $S_1FS_2$ systems. Our results reveal that by increasing the ratio of the superconducting gaps $Δ_2/Δ_1$, the critical supercurrent in a ballistic $S_1NS_2$ system can be enhanced by more than $100\%$, and reaches a saturation point, or decays away, depending on the junction thickness, magnetization strength, and chemical potential. The total critical current in a diffusive $S_1NS_2$ system was found to be enhanced by more than $50\%$ parabolically, and reaches saturation by increasing one of the superconducting gaps. In a uniform ferromagnetic junction, the supercurrent undergoes reversal by increasing $Δ_2/Δ_1>1$. Through decomposing the total supercurrent into its supergap and subgap components, our results illustrate their crucial relative contributions to the Josephson current flow. It was found that the competition of subgap and supergap currents in a $S_1FS_2$ junction results in the emergence of second harmonics in the current-phase relation. In contrast to a diffusive asymmetric Josephson configuration, the behavior of the supercurrent in a ballistic system with $Δ_2/Δ_1=1$ can be properly described by the subgap current component only, in a wide range of parameter sets, including Fermi level mismatch, magnetization strength, and junction thickness. Interestingly, when $Δ_2/Δ_1>1$, our results have found multiple parameter sets where the total supercurrent is driven by the supergap component. Therefore, our comprehensive study highlights the importance of subgap and supergap supercurrent components in both the ballistic and diffusive regimes.
