Shot noise and Coulomb effects on nonlocal electron transport in normal-metal/superconductor/normal-metal heterostructures

We argue that Coulomb interaction can strongly influence nonlocal electron transport in normal-superconducting-normal structures and emphasize direct relation between Coulomb effects and nonlocal shot noise. In the tunneling limit nonlocal differential conductance is found to have an S-like shape and can turn negative at nonzero bias. At high transmissions crossed Andreev reflection yields positive noise cross correlations and Coulomb antiblockade of nonlocal electron transport.

Figure 1

Schematics of the system under consideration.

Figure 2

[(a) and (c)] Local and [(b) and (d)] nonlocal differential conductances defined, respectively, in Eqs. (45, 46). The parameters of the system are $T=20\text{mK}$, $G_{11}=1\text{mS}$, $G_{12}=10\mu \text{S}$, and $g_1=g_2=516$. The dependencies (a) and (b) are plotted at small transmissions $T_1=0.063$ and $T_2=0.11$ while the graphs (c) and (d) correspond to fully open barriers $T_1=T_2=1$.