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

## TL;DR

This paper investigates how different processes affect the non-local shot noise and Cooper pair splitting efficiency in multi-terminal superconductor junctions, highlighting the role of pair potential symmetry and proposing a Fano factor-based testing method.

## Contribution

It introduces a method to analyze shot noise contributions in superconductor junctions and demonstrates how pair potential symmetry influences Cooper pair splitting efficiency.

## Key findings

- Crossed Andreev reflections (CAR) dominate in certain symmetries, enhancing efficiency.
- CAR contributes positively to noise cross-correlation, unlike other processes.
- Fano factor can be used to test Cooper pair splitter efficiency.

## Abstract

We analyze the non-local shot noise in a multi-terminal junction formed by two Normal metal leads con- nected 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 de- termine 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.