Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
J Phys Condens Matter. 2013 Jul 24;25(29):295301. doi: 10.1088/0953-8984/25/29/295301. Epub 2013 Jun 27.
The current-phase relation in a Josephson junction formed by putting two s-wave superconductors on the same edge of a two dimensional topological insulator is investigated. We consider the case in which the junction length is finite and magnetic impurity exists. The similarities and differences with respect to a conventional Josephson junction are discussed. Both the 2π- and 4π-period current-phase relations (I2π(ϕ),I4π(ϕ)) are studied. There is a sharp jump at ϕ = π and ϕ = 2π for I2π and I4π, respectively, in the clean junction. For I2π, the sharp jump is robust against the impurity strength and distribution. However, for I4π, an impurity makes the jump at ϕ = 2π smooth. The critical (maximum) current Ic,2π of I2π is given and we find it will be increased by an asymmetrical distribution of the impurity.
我们研究了在二维拓扑绝缘体的同一边缘放置两个 s 波超导体形成的约瑟夫森结中的电流相位关系。我们考虑了结长度有限且存在磁杂质的情况。讨论了与传统约瑟夫森结的异同。研究了 2π 和 4π 周期的电流相位关系 (I2π(ϕ),I4π(ϕ))。在干净的结中，I2π 和 I4π 分别在 ϕ = π 和 ϕ = 2π 处有明显的跳跃。对于 I2π，杂质强度和分布对明显跳跃没有影响。然而，对于 I4π，杂质会使 ϕ = 2π 处的跳跃变得平滑。我们给出了 I2π 的临界（最大）电流 Ic,2π，并且发现通过杂质的不对称分布可以增加它。
