Effect of chemical doping on heterostructured Fe-based superconductor Sr2VO3FeAs

Abstract

Phase diagrams of electron- and hole-doped Sr2VO3FeAs are investigated using Co and Mn substitution at Fe site. Metallic nature survives only for Co (electron) doping, not for Mn (hole) doping. The conductivity of Sr2VO3(Fe,M)As (M=Mn,Co) is sensitive to the structural modification of FeAs microstructure rather than carrier doping. This finding implies that the FeAs layer plays a dominant role on the charge conduction, thus the SrVO3 layers should be considered as an insulating block. Also, we found that the superconductivity is rapidly suppressed by both dopants. This result is different from the conventional behavior that superconductivity is induced by doping in the most of Fe pnictides. Our finding strongly supports the uniqueness of Sr2VO3FeAs among the Fe pnictide superconductors.