Pressure-induced shift of Tc in KxSr1-xFe2As2 (x=0.2, 0.4, 0.7): Analogy to the high-Tc cuprate superconductors

The systematic pressure shifts of T-c were investigated in the whole phase diagram of the FeAs-based superconducting compound KxSr1-xFe2As2. Different regions, arising from corresponding responses of Tc to pressure (dT(c)/dp>0, similar or equal to 0, or <0), can be clearly distinguished. This reveals an interesting similarity of the FeAs superconductors and the high-T-c cuprates. This behavior is a manifestation of the layered structure of the FeAs compounds and the pressure-induced charge transfer between the (Fe2As2) and (K/Sr) layers. The coexistence of superconductivity and spin-density wave behavior were also observed, and the pressure effects on the latter is explored.