SrFeAsF as a parent compound for iron pnictide superconductors

Abstract

We have successfully synthesized the fluo-arsenide SrFeAsF, a new parent phase with the ZrCuAsSi structure. The temperature dependence of resistivity and dc magnetization both reveal an anomaly at about T_{an} = 173 K, which may correspond to the structural and/or Spin-Density-Wave (SDW) transition. Strong Hall effect and magnetoresistance were observed below T_{an}. Interestingly, the Hall coefficient R_H is positive below T_{an}, which is opposite to the cases in the two parent phases of FeAs-based systems known so far, i.e., LnFeAsO (Ln = rare earth elements) and (Ba, Sr)Fe_2As_2 where the Hall coefficient R_H is negative. This strongly suggests that the gapping to the Fermi surfaces induced by the SDW order is more complex than we believed before that it removes the density of states on some Fermi pockets and leaves one of the electron pockets less-gapped or un-gapped. Our data clearly show that it is possible for the parent phase to have electron-like or hole-like charge carriers.

4 pages, 4 figures, to be published in Phys. Rev. B as a Rapid Communication

References in corpus (8)

• Superconductivity at 38 K in the iron arsenide (Ba1-xKx)Fe2As2
• Superconductivity at 41 K and its competition with spin-density-wave instability in layered CeO${}_{1-x}$F${}_x$FeAs
• Spin density wave anomaly at 140 K in the ternary iron arsenide BaFe2As2
• Superconductivity up to 37 K in (A1-xSrx)Fe2As2 with A=K and Cs
• LiFeAs: An Intrinsic FeAs-based Superconductor with Tc = 18K
• Thorium-doping induced superconductivity up to 56 K in Gd1-xThxFeAsO
• Superconductivity at 25 K in hole doped $(L{a}_{1-x}S{r}_x)OFeAs$
• Superconductivity at 52 K in iron-based F-doped layered quaternary compound Pr[O1-xFx]FeAs

Cited by in corpus (1)

• Band structure of tetragonal and orthorhombic fluorine-arsenide SrFeAsF as a parent phases for a new group of oxygen-free FeAs superconductors