Superconductivity in nanowires made of weak coupling superconductor materials is investigated using a Green function approach. We show that these are multigap systems in which the ratio $\Delta \left(T\right)/k_{\mathrm{B}}{T}_c$ is to a large extent similar to what is observed in some high-$T_c$ two-gap systems, such as MgB${}_2$ and some of the Fe-based superconductors. On the other hand, because of confinement, the superfluid density has a temperature behavior of the form $n_s\left(T\right)=1-{(T/T_c)}^3$ near $T_c$, thus deviating from the BCS behavior for bulk superconductors.

• Received 27 November 2011

DOI:https://doi.org/10.1103/PhysRevB.85.144504