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arXiv · 0807.4096

Superconductivity and Crystal Structures of (Ba1-xKx)Fe2As2 (x = 0 - 1)

Marianne Rotter·Michael Pangerl·Marcus Tegel·Dirk Johrendt
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Abstract

We report on doping dependencies of structural parameters and superconducting transition temperatures in the solid solution (Ba1-xKx)Fe2As2. As the main effect of doping on the crystal structure, we find linear decreasing As-Fe-As bond angles and Fe-Fe distances, equivalent to an elongation of the FeAs4 tetrahedra along [001]. The structural changes are intimately coupled to the electronic states at the Fermi level, because the most relevant Fe-3dx2-y2 orbitals are strongly affected by the As-Fe-As bond angle. Superconductivity is present over the whole doping range in (Ba1-xKx)Fe2As2 with a maximum Tc of 38 K at x ~ 0.4. The superconducting transitions in the orthorhombic compounds (Ba0.9K0.1)Fe2As2 (Tc ~ 3 K) and (Ba0.8K0.2)Fe2As2 (Tc ~ 25 K) is strong evidence for the coexistence of superconductivity with the structurally distorted and potentially magnetically ordered state in the BaFe2As2 family of iron arsenide superconductors.

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Marianne Rotter, Michael Pangerl, Marcus Tegel, Dirk Johrendt. 2008-08-12. Superconductivity and Crystal Structures of (Ba1-xKx)Fe2As2 (x = 0 - 1). https://doi.org/10.1002/anie.200803641

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