Abstract
The in-plane optical properties of the inhomogeneous iron-chalcogenide superconductor with a critical temperature have been modeled in the normal state using the Bruggeman effective medium approximation for metallic inclusions in an insulating matrix. The volume fraction for the inclusions is estimated to be ; however, they appear to be highly distorted, suggesting a filamentary network of conducting regions joined through weak links. The value for the plasma frequency in the inclusions is much larger than the volume average, which when considered with the reasonably low values for the scattering rate , suggests that the transport in the grains is always metallic. Estimates for the dc conductivity and the superfluid density in the grains place the inclusions on the universal scaling line close to other homogeneous iron-based superconductors.
- Received 17 August 2012
DOI:https://doi.org/10.1103/PhysRevB.86.144530
©2012 American Physical Society