Thermal fluctuation conductivity and dimensionality in iron-based superconductors

The time-dependent Ginzburg-Landau Lawrence-Doniach model is used to investigate the superconducting fluctuation electrical conductivities. The theoretical result based on the self-consistent Gaussian approximation is used to fit the transport measurement data of iron-based superconductors F-doped LaOFeAs and BaFe_2-xNi_xAs₂. We demonstrate that LaOFeAs shows layered behavior, while BaFe_2-xNi_xAs₂ is more of a 3D feature. The conductivity in the region near T_c is well described by the theoretical formula.