Optical study of charge dynamics in CaCo2As2.

We present an infrared spectroscopy study of charge dynamics in CaCo2As2 single crystal. In this material, the optical conductivity can be described by two Drude components with different scattering rates (1/τ): a broad incoherent background and a narrow Drude component. By monitoring the temperature dependence, we find that only the narrow Drude component is temperature-dependent and determines the transport properties. Especially a Fermi liquid behavior of carriers is revealed by the T2 behavior in the dc resistivity ρn and scattering rate 1/τn, indicating a coherent nature of quasiparticles in the narrow Drude subsystem. [ABSTRACT FROM AUTHOR]