Abstract
The electrodynamic properties of and single crystals have been investigated by reflectivity measurements in a wide frequency range. In the metallic state, the optical conductivity consists of a broad incoherent background and a narrow Drude-type component which determines the transport properties; only the latter contribution strongly depends on the composition and temperature. This subsystem reveals a behavior in the dc resistivity and scattering rate disclosing a hidden Fermi-liquid behavior in the 122 iron pnictide family. An extended Drude analysis yields the frequency dependence of the effective mass (with in the static limit) and scattering rate that does not disclose a simple power law. The spectral weight shifts to lower energies upon cooling; a significant fraction is not recovered within the infrared range of frequencies.
3 More- Received 9 April 2010
DOI:https://doi.org/10.1103/PhysRevB.82.054518
©2010 American Physical Society