Low-temperature transport through a quantum dot: Finite-$U$ results and scaling behavior

We calculate the conductance through a quantum dot weakly coupled to metallic leads, modeled by the spin-1/2 Anderson model with finite Coulomb repulsion U. We adopt the noncrossing approximation method in its finite-$U$ extension. Our results can be compared to those obtained with the exact numerical renormalization group method, and good agreement is found both in the high-temperature (Coulomb blockade) and in the low-temperature (Kondo) regime. We analyze the scaling properties of the low-temperature conductance, and calculate the universal function that describes the electronic transport in the Kondo regime. Very good agreement with recent experimental results is found. Finally, we suggest a simple interpolating function that fits fairly well the calculated conductance in a broad temperature range.