Andreev reflection and Josephson effect in the α−T3 lattice

Abstract

We investigate the Andreev reflection and the Josephson effect in the α−T3 lattice, which falls between graphene (α=0) and the dice lattice (α=1), by adjusting the parameter α. In the regime of the specular Andreev reflection, when the incident energy of the electron is small, the probability of Andreev reflection decreases as the parameter α increases. On the contrary, when the incident energy is large, the probability of Andreev reflection increases as the parameter α increases. Interestingly, when the incident energy approaches the superconducting energy gap function, the Andreev reflection with approximate all-angle perfect transmission happens in the case of α=1. In the regime of Andreev retroreflection, when the parameter α increases, the probability of Andreev reflection increases regardless of the value of incident energy. When the incident energy approaches the superconducting energy gap function, the Andreev reflection with approximate all-angle perfect transmission happens regardless of the value of α. We also give the differential conductance in these two regimes and find that it increases as the parameter α increases generally. In addition, the α−T3 lattice-based Josephson current increases as α increases. When the length of the junction approaches zero, the critical Josephson currents in the different values of α approach the same value.

Source-reported materials — not catalogue approval

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