Crossed Andreev reflection in a graphene bipolar transistor

TL;DR

This paper studies crossed Andreev reflection in a graphene bipolar transistor, revealing unique conductance oscillations and suppression of certain reflections without spin or valley polarization.

Contribution

It demonstrates the elimination of electron elastic cotunneling and local Andreev reflection in n- and p-type graphene leads without polarization, and predicts conductance oscillations.

Findings

Elimination of electron elastic cotunneling and local Andreev reflection.

Oscillations of conductances as a function of interface distance.

Conductance behavior without valley-isospin or spin polarizations.

Abstract

We investigate the crossed Andreev reflections between two graphene leads connected by a narrow superconductor. When the leads are respectively of the n-and p- type, we find that electron elastic cotunneling and local Andreev reflection are both eliminated even in the absence of any valley-isospin or spin polarizations. We further predict oscillations of both diagonal and cross conductances as a function of the distance between the graphene-superconductor interfaces.