Anisotropic zero-resistance onset in organic superconductors

We study the coexistence of superconductivity (SC) and density-wave state and reconcile various puzzling experimental data in organic superconductors (TMTSF)2 PF6 and (TMTSF)2 ClO4 . The anisotropic resistance drop above Tc is qualitatively described by nascent isolated SC islands within a bulk analytical model. However, the observed anisotropic SC onset is explained only when the finite size and flat needle shape of samples is considered. Our results pave a way to estimate the volume fraction and the typical size of SC islands far from the sample surface and apply to many inhomogeneous superconductors, including highTc cuprate or Fe-based ones.