Pressure Suppression of Spin-Density-Wave Gap in the Optical Conductivity of SrFe^sub 2^As^sub 2

Optical reflectance R(...) of a pressure-induced superconductor ... has been measured under external pressure to 6 GPa and at temperatures to 8 K. Optical conductivity ...(...) has been derived from the measured R(...). At ambient pressure, in the antiferromagnetic state below TN=198 K, a pronounced feature develops in ...(...) due to the opening of a spin density wave (SDW) gap, as already reported in the literature. With increasing pressure, the SDW gap feature in ...(...) is progressively suppressed. At 4 GPa, where the sample is superconducting, the SDW gap feature in ...(...) is strongly reduced than that at ambient pressure, but is still clearly observed. At 6 GPa, the SDW gap is completely suppressed. The evolution of SDW gap feature with pressure is qualitatively similar to that with chemical doping previously reported. (ProQuest: ... denotes formulae/symbols omitted.)