Optical Study of BaFe2As2 under pressure: Coexistence of spin-density-wave gap and superconductivity
Abstract
Temperature-dependent reflectivity measurements in the frequency range 85 - 7000 cm-1 were performed on BaFe2As2 single crystals under pressure up to 5 GPa. The corresponding pressure- and temperature-dependent optical conductivity was analyzed with the Drude-Lorentz model to extract the coherent and incoherent contributions. The gradual suppression of the spin-density wave (SDW) state with increasing pressure and the appearance of the superconducting phase coexisting with the SDW phase at 3.6~GPa were observed. At 3.6~GPa, the reflectivity reaches unity below 95~cm-1 indicating the opening of the superconducting gap and shows a full gap tendency at 6 K.
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