Single-crystal growth and optical conductivity of SrPt 2 As 2 superconductors

摘要: SrPt${}_{2}$As${}_{2}$ single crystals with CaBe${}_{2}$Ge${}_{2}$-type structure were synthesized by self-melting technique. X-ray diffraction, transmission electron microscopy, electrical resistivity, magnetic susceptibility, specific heat, and optical spectroscopy measurements conducted to elucidate the properties of SrPt${}_{2}$As${}_{2}$. undergo a structural phase transition well above room temperature (about 450 K) become superconducting at 5.18 K. The temperatures are reduced 6$%$ iridium doping. Both pure Ir-doped demonstrated be highly metallic rather high plasma frequencies. In particular, measurement revealed two gaplike suppression structures: stronger one energy near 12 000 cm${}^{\ensuremath{-}1}$ ($\ensuremath{\sim}$1.5 eV), less prominent lower 3200 ($\ensuremath{\sim}$0.4 eV) for compound. We elaborate that former is related correlation effect, while latter could attributed partial gap formation associated transition.