Superconductivity in Ca1-xLaxFeAs2: A Novel 112-Type Iron Pnictide with Arsenic Zigzag Bonds

We report superconductivity in the novel 112-type iron-based compound Ca1-xLaxFeAs2. Single-crystal X-ray diffraction analysis revealed that the compound crystallizes in a monoclinic structure (space group \(P2_{1}\)), in which Fe2As2 layers alternate with Ca2As2 spacer layers such that monovalent arsenic forms zigzag chains. Superconductivity with a transition temperature (\(T_{\text{c}}\)) of 34 K was observed for the \(x = 0.1\) sample, while the \(x = 0.21\) sample exhibited trace superconductivity at 45 K. First-principles band calculations demonstrated the presence of almost cylindrical Fermi surfaces, favorable for the high \(T_{\text{c}}\) in La-doped CaFeAs2.

[1]  K. Kudo,et al.  Emergence of superconductivity at 45 K by lanthanum and phosphorus co-doping of CaFe2As2 , 2013, Scientific Reports.

[2]  Tatsuo C. Kobayashi,et al.  Iron?platinum?arsenide superconductors Ca10(PtnAs8)(Fe2-xPtxAs2)5 , 2012, 1203.0821.

[3]  E. Nishibori,et al.  Superconductivity at 38 K in Iron-Based Compound with Platinum–Arsenide Layers Ca10(Pt4As8)(Fe2-xPtxAs2)5 , 2011, 1108.0029.

[4]  D. Johrendt,et al.  Superconductivity up to 35 K in the iron platinum arsenides (CaFe(1-x)Pt(x)As)10Pt(4-y)As8 with layered structures. , 2011, Angewandte Chemie.

[5]  H. Eisaki,et al.  Superconductivity at 28.3 and 17.1 K in (Ca4Al2O6-y)(Fe2Pn2) (Pn = As and P) , 2010, 1008.2586.

[6]  Y. Ikuhara,et al.  A new homologous series of iron pnictide oxide superconductors (Fe2As2)(Can + 2(Al, Ti)nOy) (n = 2, 3, 4) , 2010, 1008.2582.

[7]  Shinya Sato,et al.  Homologous series of iron pnictide oxide superconductors (Fe2As2)[Can+1(Sc,Ti)nOy] (n=3,4,5) with extremely thick blocking layers , 2010, 1006.2355.

[8]  K. Kishio,et al.  New Iron Arsenide Oxides (Fe2As2)(Sr4(Sc,Ti)3O8), (Fe2As2)(Ba4Sc3O7.5), and (Fe2As2)(Ba3Sc2O5) , 2010, 1006.2353.

[9]  H. Rosner,et al.  Lattice distortions in layered type arsenides LnTAs2 (Ln=La–Nd, Sm, Gd, Tb; T=Ag, Au): Crystal structures, electronic and magnetic properties , 2010 .

[10]  Shinya Sato,et al.  Superconductivity in a new iron pnictide oxide (Fe2As2)(Sr4(Mg, Ti)2O6) , 2009, 0909.2945.

[11]  Peng Cheng,et al.  Transition of stoichiometric Sr2VO3FeAs to a superconducting state at 37.2 K , 2009, 0904.1732.

[12]  K. Kishio,et al.  New Series of Nickel-Based Pnictide Oxide Superconductors (Ni2Pn2)(Sr4Sc2O6) (Pn = P, As) , 2009, 0904.0825.

[13]  K. Kishio,et al.  New iron-based arsenide oxides (Fe2As2)(Sr4M2O6)(M = Sc, Cr) , 2009, 0903.5124.

[14]  G. Kotliar,et al.  Density-functional calculations of the electronic structures and magnetism of the pnictide superconductors BaFeAs 2 and BaFeSb 2 , 2009 .

[15]  X. H. Chen,et al.  Superconductivity at 56 K in samarium-doped SrFeAsF , 2008, Journal of physics. Condensed matter : an Institute of Physics journal.

[16]  M. V. Sadovskii,et al.  Electronic structure of new AFFeAs prototype of iron arsenide superconductors , 2008, 0810.3377.

[17]  H. Hosono,et al.  Superconductivity induced by co-doping in quaternary fluoroarsenide CaFeAsF. , 2008, Journal of the American Chemical Society.

[18]  J. Tapp,et al.  LiFeAs: An intrinsic FeAs-based superconductor with Tc=18 K , 2008, 0807.2274.

[19]  Liling Sun,et al.  Superconductivity at 55 K in Iron-Based F-Doped Layered Quaternary Compound Sm[O1-xFx] FeAs , 2008 .

[20]  Marcus Tegel,et al.  Superconductivity at 38 K in the iron arsenide (Ba1-xKx)Fe2As2. , 2008, Physical review letters.

[21]  M. Du,et al.  Density functional study of LaFeAsO(1-x)F(x): a low carrier density superconductor near itinerant magnetism. , 2008, Physical review letters.

[22]  Hideo Hosono,et al.  Iron-based layered superconductor La[O(1-x)F(x)]FeAs (x = 0.05-0.12) with T(c) = 26 K. , 2008, Journal of the American Chemical Society.

[23]  W. Jeitschko,et al.  Ternary Arsenides ACuAs2 and Ternary Antimonides AAgSb2 (A = Rare-Earth Elements and Uranium) with HfCuSi2-Type Structure , 1995 .