Andreev reflection in a normal-superconductor-normal junction based on type-II Weyl semimetal

Abstract

The quantum transport behavior of the normal-superconductor-normal (NSN) junction is studied theoretically based on a type-II Weyl semimetal which is rotated a certain angle. The calculation results show that the orientation angle determines the scattering mechanism of the system. In the NSN junction, there exist simultaneously two local Andreev reflections (ARs) (retro AR and specular AR) and two local election transmissions (ETs) (retro ET and specular ET) when the orientation angle is small. Moreover, the retro AR is gradually suppressed with the further increase of the orientation angle. When the orientation angle exceeds the critical angle, the scattering mechanism in NSN junction is the same as that of the NSN junction in normal mental, i.e. the normal electron reflection, normal electron transmission, retro Andreev reflection and crossed Andreev reflection take place simultaneously. In addition, the total conductance of the system is unaffected by the chemical potential, nor by the incident angle when the orientation angle is smaller than the critical angle, but decreases with the increase of the incident angle when the orientation angle is greater than the critical angle. The conductance of crossed Andreev reflection increases with incident angle increasing under some conditions.