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A Perfect Andreev Reflection Induced by Anderson Disorder in a Normal–Superconductor Junction
Author(s) -
Zhang Shu-feng,
Zhang Tian-yi
Publication year - 2021
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.202100192
Subject(s) - andreev reflection , condensed matter physics , physics , superconductivity , scattering , electron , anderson localization , quantum mechanics
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.