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A Perfect Andreev Reflection Induced by Anderson Disorder in a Normal–Superconductor Junction
Physica Status Solidi (B) - Basic Solid State Physics ( IF 1.5 ) Pub Date : 2021-05-22 , DOI: 10.1002/pssb.202100192
Shu-feng Zhang 1 , Tian-yi Zhang 2
Affiliation  

The electronic transport properties of a 2D normal metal superconductor are studied by a nonequilibrium Green's function method. The normal metal is the non-inverted HgTe/CdTe quantum well doped by electrons. It is found that Andreev reflection (AR) is enhanced in the weak disorder regime while weakened in the strong disorder regime. However, the AR coefficient can be perfect ( T A = 1 ) with vanished fluctuations in the moderate disorder regime, whereas other scattering processes are forbidden. The mechanism goes that Anderson disorder leads to a topological Anderson insulator with bulk states localized while edge states still extensive. Multiple ARs and spin-momentum locking cooperate to vanish the normal reflection and leave AR only. A detailed numerical study shows that fixing the Fermi surface in conduction band, a large enough junction width, and a strong coupling between the normal and superconducting leads are necessary for perfect AR.

中文翻译:

安德森障碍在正常-超导体结中引起的完美安德列夫反射

通过非平衡格林函数方法研究二维普通金属超导体的电子输运特性。普通金属是由电子掺杂的非反转 HgTe/CdTe 量子阱。发现安德列夫反射(AR)在弱无序状态下增强,而在强无序状态下减弱。然而,AR系数可以是完美的( 一种 = 1 ) 在中度无序状态下波动消失,而其他散射过程被禁止。其机制是安德森无序导致拓扑安德森绝缘体,体态局部化而边缘态仍然广泛。多个 AR 和自旋动量锁定合作消除法向反射,只留下 AR。详细的数值研究表明,将费米面固定在导带中、足够大的结宽度以及正常和超导引线之间的强耦合是完美 AR 所必需的。
更新日期:2021-05-22
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