Theory of fluctuation conductivity from interband pairing in pnictide superconductors

Abstract

We derive the effective action for superconducting fluctuations in a four-band model for pnictides, discussing the emergence of a single critical mode out of a dominant interband pairing mechanism. We then apply our model to calculate the paraconductivity in two-dimensional and layered three-dimensional systems and compare our results with recent resistivity measurements in SmFeAsO(0.8)F(0.2)

Fluctuation conductivity in two-band superconductor SmFeAsO0.8F0.2

“…1. For comparison of the calculations, the experimental data of the fluctuation conductivity in SmFeAsO 1−x F x [14] are also presented in this figure. For the theoretical calculations the following fitting parameters were used: T c = 55 K, T c1 ≈ 12.5 K, T c2 ≈ 26.8 K,…”

“…The results of the calculations, obtained by using Aslamazov-Larkin expression (7) with modified parameters for temperature dependence (14) are presented in the Fig. 1.…”

“…Experimental results for fluctuation conductivity in SmFeAsO 1−x F x presented in Fig. 1 by full squares were taken from the study [14]. Results of calculations using two-band GinzburgLandau theory reduced to the effective single-band case, are shown by triangles in Fig.…”

“…The four-band Eliashberg model was applied for the study of thermodynamic properties of Fe-based compounds in paper [13]. Recently, the fluctuation conductivity of SmFeAsO 1−x F x has been measured in study [14]. They found that the fluctuation conductivity cannot be described by the standard Ginzburg-Landau theory with a single isotropic energy band.…”

“…Fitting parameters for calculation of fluctuation conductivity were taken from the microscopic theory for SmFeAsO 1−x F x compound. Finally, the results of calculations were compared with the experimental data [14].…”