Abrupt Emergence of Pressure-Induced Superconductivity of 34 K in SrFe2As2: A Resistivity Study under Pressure

We report resistivity measurement under pressure in single crystals of SrFe_2As_2, which is one of the parent materials of Fe-based superconductors. The structural and antiferromagnetic (AFM) transition of T_0 = 198 K at ambient pressure is suppressed under pressure, and the ordered phase disappears above P_c ~ 3.6-3.7 GPa. Superconductivity with a sharp transition appears accompanied by the suppression of the AFM state. T_c exhibits a maximum of 34.1 K, which is realized close to the phase boundary at P_c. This T_c is the highest among those of the stoichiometric Fe-based superconductors.