Scattering and transport properties of tight-binding random networks

We study numerically scattering and transport statistical properties of tight-binding random networks characterized by the number of nodes $N$ and the average connectivity $\alpha$. We use a scattering approach to electronic transport and concentrate on the case of a small number of single-channel attached leads. We observe a smooth crossover from insulating to metallic behavior in the average scattering matrix elements \bra |S_{mn}|^2 \ket, the conductance probability distribution $w(T)$, the average conductance \bra T \ket, the shot noise power $P$, and the elastic enhancement factor $F$ by varying $\alpha$ from small ($\alpha \to 0$) to large ($\alpha \to 1$) values. We also show that all these quantities are invariant for fixed $\xi=\alpha N$. Moreover, we proposes a heuristic and universal relation between \bra |S_{mn}|^2 \ket, \bra T \ket, and $P$ and the disorder parameter $\xi$.