Interaction between two structural blocks and its correlation with superconductivity in SmFeAsO1-xFx and SmFe1-xMxAsO (M = Co,Ni)
Department of Physics, China Jiliang University - Hangzhou 310018, PRC
2 State Key Lab of Silicon Materials, Zhejiang University - Hangzhou 310027, PRC
3 Department of Physics, Zhejiang University - Hangzhou 310027, PRC
Accepted: 19 August 2010
Based on a block model, we developed a program to calculate the cohesive energy of the whole cell and the combinative energy between the Fe-As block and the Sm-O block in SmFeAsO1−xFx and SmFe1−xMxAsO (M = Co,Ni). A relationship between the combinative energy and Tc is established, which is similar to the previous reports in cuprate HTSCs to some extent. While the nearly unchanged combinative energy in SmFe1−xMxAsO (M = Co,Ni), no matter whether the electron is supposed to be at the Fe, As site or at the centre of the Fe-As layer, indicates an itinerant character in SmOFeMAs (M = Co,Ni), which is severely different from the local carrier picture in the cuprate HTSCs. We suggest that the relationship can be understood by the charge-transfer models. Our results may shed light on the similarities and differences in understanding the superconductivity of the two important kinds of HTSCs.
PACS: 61.66.Fn – Inorganic compounds / 61.50.Lt – Crystal binding; cohesive energy / 74.70.Dd – Ternary, quaternary, and multinary compounds (including Chevrel phases, borocarbides, etc.)
© EPLA, 2010