Noise cross-correlation and Cooper pair splitting efficiency in multi-teminal superconductor junctions

Abstract

We analyze the non-local shot noise in a multi-terminal junction formed by two Normal metal leads connected to one superconductor. Using the cross Fano factor and the shot noise, we calculate the efficiency of the Cooper pair splitting. The method is applied to d-wave and iron based superconductors. We determine that the contributions to the noise cross-correlation are due to crossed Andreev reflections (CAR), elastic cotunneling, quasiparticles transmission and local Andreev reflections. In the tunneling limit, the CAR contribute positively to the noise cross-correlation whereas the other processes contribute negatively. Depending on the pair potential symmetry, the CAR are the dominant processes, giving as a result a high efficiency for Cooper pair split. We propose the use of the Fano factor to test the efficiency of a Cooper pair splitter device.

Long-range Cooper pair splitting by chiral Majorana edge states

“…The basic structure of such devices consists of a superconducting region (S) connected to two normal electrodes (N) separated by a distance of the order of the superconducting coherence length ξ 0 . Various designs include intermediate quantum dots [30][31][32][33][34][35][36][37][38][39], anisotropic superconductivity [2,11,[40][41][42], and some devices have been realized experimentally [14,15,17,19,22,[32][33][34]. For subgap voltages, CARs compete with local Andreev reflections (AR) and elastic co-tunneling (EC) between electrodes.…”

Crossed Andreev reflection in zigzag phosphorene nanoribbon based ferromagnet/superconductor/ferromagnet junctions

“…It is desirable to find large probability and convenient manipulation of CAR in electronic devices, as the reversed process of CAR is practical in generating nonlocal entangled-electrons 2 – 4 . Nowadays, the normal/superconductor/normal (N/S/N) junction had been used to detect CAR 5 , 6 , where the superconductivity of the junction can be induced by the proximity effect. At the same time, the discovery of graphene 7 – 10 become a breakthrough in the field of two-dimensional material.…”

Crossed Andreev Reflection in Zigzag Phosphorene Nanoribbon Based Ferromagnet/Superconductor/Ferromagnet Junctions

“…It is desirable to find electronic devices with a large probability and convenient manipulation of CAR, as the reversed process of CAR is practical in generating nonlocal entangled-electrons [2][3][4] . Nowadays, the normal/superconductor/normal (N/S/N) junction had been used to detect CAR 5,6 , where the superconductor in the junction can be induced by the proximity effect.At the same time, the discovery of graphene [7][8][9][10] become a breakthrough in the field of two-dimensional material. Studies of CAR in graphene based superconductor junctions were reported since then.…”