We analyze the charge transport through a single level quantum dot coupled to a normal and superconducting lead where the electron pairs exist either as the coherent (for temperatures below $T_c$) or incoherent objects (in a region $T_c<T<T^{*}$). Practically, this situation can be encountered using the high $T_c$ superconducting materials where precursor effects have been observed upon approaching $T_c$ from above. Without restricting to any particular microscopic mechanism, we investigate the qualitative properties of nonequilibrium charge current caused by the electron pair coherence.

• Received 18 December 2006

DOI:https://doi.org/10.1103/PhysRevB.76.104514