Superfluid density of Ba(Fe$_{1-x}M_x$)$_2$As$_2$ from optical experiments

D. Wu; N. Barisic; N. Drichko; P. Kallina; A. Faridian; B. Gorshunov; M. Dressel; L. J. Li; X. Lin; G. H. Cao; Z. A. Xu

doi:10.1016/j.physc.2009.10.142

paper

Superfluid density of Ba(Fe $_{1 - x} M_{x}$ ) $_{2}$ As $_{2}$ from optical experiments

arXiv:0912.0849 · doi:10.1016/j.physc.2009.10.142

Abstract

The temperature dependence of the $ab$ -plane optical reflectivity of Ba(Fe $_{0.92}$ Co $_{0.08})_{2}$ As $_{2}$ and Ba(Fe $_{0.95}$ Ni $_{0.05})_{2}$ As $_{2}$ single crystals is measured in a wide spectral range. Upon entering the superconducting regime, the reflectivity in both compounds increases considerably at low frequency, leading to a clear gap in the optical conductivity below 100 cm $^{- 1}$ . From the analysis of the complex conductivity spectra we obtain the penetration depth $λ (T) = (3500 \pm 350)$ Åfor Ba(Fe $_{0.92}$ Co $_{0.08})_{2}$ As $_{2}$ and $(3000 \pm 300)$ Åfor Ba(Fe $_{0.95}$ Ni $_{0.05})_{2}$ As $_{2}$ . The calculated superfluid density $ρ_{s}$ of both compounds nicely fits the scaling relation $ρ_{s} = (125 \pm 25) σ_{d c} T_{c}$ .

2pages,2figures

Superfluid density of Ba(Fe1−x​Mx​)2​As2​ from optical experiments

Abstract

Superfluid density of Ba(Fe $_{1 - x} M_{x}$ ) $_{2}$ As $_{2}$ from optical experiments