Structural, Magnetic, And Electronic Transport Properties Of Hole-Doped Srfe2-Xcuxas2 Single Crystals

We report the structural, magnetic, and electronic transport properties of SrFe2-xCuxAs2 single crystals grown by a self-flux technique. Both SrCu2As2 and SrFe2As2 crystallize in a ThCr2Si2-type (122-type) structure at room temperature, but exhibit distinct magnetic and electronic transport properties. According to the x-ray photoelectron spectroscopy Cu 2p core line position, resistivity, susceptibility, and positive Hall coefficient, SrCu2As2 is an sp-band metal with Cu in the 3d(10) electronic configuration corresponding to the valence state Cu1+. Compared with SrCu2As2, the almost unchanged Cu 2p core line position in SrFe2-xCuxAs2 indicates that partial Cu substitutions for Fe in SrFe2As2 may result in hole doping rather than the expected electron doping. No superconductivity is induced by Cu substitution on Fe sites, even though the structural/spin density wave transition is gradually suppressed with increasing Cu doping. DOI: 10.1103/PhysRevB.87.075105