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Superconducting State in SrFe 2 − x Co x As 2 by Internal Doping of the Iron Arsenide Layers

2008; American Physical Society; Volume: 101; Issue: 20 Linguagem: Inglês

10.1103/physrevlett.101.207004

1092-0145

Andreas Leithe‐Jasper, Walter Schnelle, C. Geibel, H. Rösner,

Corporate Taxation and Avoidance

In the strontium iron-cobalt arsenides SrFe2-xCoxAs2 (0.2 < or = x < or = 0.4) superconductivity with T_{c} up to 20 K is observed in magnetic susceptibility, electrical resistivity, and specific heat data. This first observation of bulk superconductivity induced by electron doping in this family of compounds-despite strong disorder in the Fe-As layer-favors an itinerant electronic theory in contrast to the strongly correlated cuprates and renders a p- or d-wave pairing unlikely. The magnetic ordering present in SrFe2As2 is rapidly suppressed by substitution of Fe by Co. Density functional theory calculations show that this is due to a rigid downshift of the Fe-3d_{x;{2}-y;{2}}-related band edge in the density of states.