Superconductivity in Uncollapsed Tetragonal LaFe2As2

Abstract

We report synthesis, crystal structure and superconductivity in ThCr2Si2-type LaFe2As2 (La122). La122 was synthesized at 960°C for 1.5 h under a pressure of 3.4 GPa. An as-synthesized La122 (non-superconductor) had a collapsed tetragonal structure with a short c-axis length of 11.0144(4) Å as observed in CaFe2As2 under pressure. The collapsed tetragonal transformed into an uncollapsed tetragonal by annealing the as-synthesized La122 at 500°C. The c-axis length remarkably extended to 11.7317(4) Å and superconductivity emerged at 12.1 K in the uncollapsed tetragonal La122. A cylindrical hole-like Fermi-surface around the Γ point that plays an important role for an s+-wave paring in iron-based superconductors was missing in the uncollapsed tetragonal La122 due to heavily electron-doping. Superconductivity in La122 may be closely related to that induced in CaFe2As2 under pressure.

8 pages, 7 figures, 1 table

References in corpus (17)

• Superconductivity at 38 K in the iron arsenide (Ba1-xKx)Fe2As2
• Superconductivity at 43 K in Samarium-arsenide Oxides $SmFeAs{O}_{1-x}{F}_x$
• Unconventional pairing originating from disconnected Fermi surfaces in superconducting LaFeAsO${}_{1-x}$F${}_x$}
• Superconductivity and Phase Diagram in the Iron-based Arsenic-oxides ReFeAsO1-delta (Re = rare earth metal) without F-Doping
• Effect of Structural Parameters on Superconductivity in Fluorine-Free LnFeAsO1-y (Ln=La,Nd)
• Pressure induced superconductivity in CaFe${}_2$As${}_2$
• Superconductivity at 25 K in hole doped $(L{a}_{1-x}S{r}_x)OFeAs$
• Pressure-induced volume-collapsed tetragonal phase of CaFe2As2 as seen via neutron scattering
• Different resistivity response to spin density wave and superconductivity at 20 K in $C{a}_{1-x}N{a}_{x}F{e}_{2}A{s}_2$
• Pressure-induced superconductivity in single crystal CaFe2As2
• Hydrogen in layered iron arsenide: indirect electron doping to induce superconductivity
• Electronic and magnetic structures of ternary iron selenides AFe${}_2$Se${}_2$ (A=K, Cs, or Tl)
• Emergence of superconductivity at 45 K by lanthanum and phosphorus co-doping of CaFe2As2
• Structural and electronic response upon hole-doping of rare-earth iron oxyarsenides Nd1-xSrxFeAsO (0 < x < 0.2)
• Density Functional Study of the Over-Doped Iron Chalcogenide: TlFe${}_2$Se${}_2$ with ThCr${}_2$Si${}_2$ structure
• Fermi-Surface Reconstruction and Complex Phase Equilibria in CaFe${}_2$As${}_2$
• Magnetic and structural transitions in La${}_{0.4}$Na${}_{0.6}$Fe${}_2$As${}_2$ single crystals