Optical Properties in The Hole-Doped Ca8.5Na1.5(Pt3As8)(Fe2As2)5 Single Crystal

For newly synthesized hole-doped Ca 8.5 Na 1.5 (Pt 3 As 8 )(Fe 2 As 2 ) 5 single crystals, we measured the infrared reflectivity spectrum and the magnetic field dependence of magnetoresistivity and Hall resistivity. The results of these two experiments in normal states are well described by two band models. In the normal state below 150 K, the optical conductivity spectrum shows a transfer of spectral weights from the mid-infrared region to the near-infrared region. Meanwhile, the magnetoresistance and Hall resistance show a significant decrease in carrier density at 150 K. These two phenomena are due to the conversion of itinerant electrons to heavy electrons by the strong correlation effect, Hund's coupling. In the superconducting state, the spectral weight in the low frequency region by the superconducting condensate is completely suppressed, which is well analyzed by the generalized Mattis-Bardeen (M-B) model with a two superconducting gap.