狭窄的二维拓扑绝缘体超导结中新奇的0-π态转变

发布时间：2018-06-29 18:41

本文选题：狭窄的二维拓扑绝缘体 + 边间耦合　；参考：《南京师大学报(自然科学版)》2017年03期

【摘要】：边间耦合引起的边间背散射是赋予狭窄的二维拓扑绝缘体的重要特性,能够大大地丰富拓扑超导电子学.本文在考虑边间耦合的情况下,使用基于Bogoliubov-de Gennes(BdG)方程的理论方法,研究了由狭窄的二维拓扑绝缘体构成的Josephson结,其中两个相距长度为d的超导电极置于同一边上.结果发现,通过改变d总可以导致0-π态转变,同时这0-π态转变能反过来证明边缘态螺旋性的自旋结构.引起这个新奇的结果的机制源于边间背散射引诱了一个额外的π相移,不同于由两个超导电极间铁磁体夹层厚度变化所引起的传统的0-π态转变.此外,在0-π态转变点处存在相当大的Josephson临界电流残余值.因此,这些结果在超导电子学器件的设计中具有潜在的应用价值,譬如,高性能的超流开关.
[Abstract]:Inter-edge backscattering caused by inter-edge coupling is an important characteristic of giving narrow two-dimensional topological insulators, which can greatly enrich topological superconducting electronics. In this paper, using the Bogoliubov-de Gennes (BdG) equation, a Josephson junction consisting of a narrow two-dimensional topological insulator is studied, in which two superconducting electrodes with d distance are located on the same side. It is found that the transformation of 0- 蟺 states can always be induced by changing d, and the spin structure of the helicity of the edge states can be proved by the transformation of the 0- 蟺 states in turn. The mechanism of this novel result is due to the fact that the edge-to-side backscattering induces an extra 蟺 phase shift, which is different from the traditional 0- 蟺 state transition caused by the thickness change of ferromagnet interlayer between two superconducting electrodes. In addition, there is a considerable residual value of Josephson critical current at the transition point of 0-蟺 state. Therefore, these results have potential applications in the design of superconducting electronic devices, such as high performance supercurrent switches.
【作者单位】：南京师范大学物理科学与技术学院;
【基金】：江苏省普通高校研究生科研创新计划项目(KYLX16_1266)
【分类号】：O469

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