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Iron arsenide superconductors (CaFeAs) 10 M n As 8 with metallic interlayers ( M = Pt, Pd; n = 3, 4)
Author(s) -
Stürzer Tobias,
Stürzer Christine,
Johrendt Dirk
Publication year - 2017
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201600417
Subject(s) - arsenide , superconductivity , materials science , condensed matter physics , crystallography , doping , fermi surface , chemistry , gallium arsenide , physics
The compounds referred to as 1038 and 1048 phases (CaFeAs) 10 Pt n As 8 ( n = 3,4) are the structurally most complex iron arsenide superconductors and the first examples with metallic interlayers. The electronic subsystems of FeAs and Pt n As 8 layers hardly interact and the contribution of the metallic Pt n As 8 interlayers to the Fermi surface is so small that the typical nesting is not degraded. (CaFeAs) 10 Pt 3 As 8 is the parent compound of the 1038/1048 materials which undergoes the typical magneto‐structural phase transition in spite of the already triclinic lattice. Superconductivity is controlled by the same doping mechanisms as known from simpler FeAs systems. High critical temperatures up to 38 K occur in both 1038 and 1048 phases if the FeAs layers are clean (free from Pt) and electron doped by charge transfer either from Pt 4 As 8 in 1048 or by rare‐earth doping of the calcium layer in 1038 compounds. The presence of two negatively charged layers (FeAs) δ − and (Pt n As 8 ) δ − which compete for the electrons transferred from the Ca 2+ ions is unique in the family of iron arsenide superconductors. Geometric incompatibilities of the FeAs and Pt n As 8 slabs cause severe stacking disorder. The robustness of superconductivity against low lattice symmetry and significant structural imperfection of the interlayer is quite remarkable and underlines that the FeAs slabs are the key in controlling and understanding high‐temperature superconductivity in iron arsenides. Crystal structure of (CaFeAs) 10 Pt 3 As 8 and the Pt 3 As 8 layer.