Strain-modulated anisotropic Andreev reflection in a graphene-based superconducting junction

We investigate the Andreev reflection across a uniaxial strained graphene-based superconducting junction. Compared with pristine graphene-based superconducting junction, three opposite properties are found. Firstly, in the regime of the interband conversion of electron-hole, the Andreev retro-reflection happens. Secondly, in the regime of the intraband conversion of electron-hole, the specular Andreev reflection happens. Thirdly, the perfect Andreev reflection, electron-hole conversion with unit efficiency, happens at a nonzero incident angle of electron. These three exotic properties arise from the strain-induced anisotropic band structure of graphene, which breaks up the original relation between the direction of velocity of particle and the direction of the corresponding wavevector. Our finding gives an insight into the understanding of Andreev reflection and provides an alternative method to modulate the Andreev reflection.

Automated summary

This study investigates the Andreev reflection across a uniaxial strained graphene-based superconducting junction. Compared to the pristine junction, three opposite properties are found: Andreev retro-reflection in the interband conversion regime, specular Andreev reflection in the intraband conversion regime, and perfect Andreev reflection with unit efficiency at a nonzero incident angle of electron. These exotic properties arise from the strain-induced anisotropic band structure of graphene, breaking the original relation between particle velocity direction and corresponding wavevector direction.