The local lattice structure in LaFeAsO1-x Fx superconductors is studied by extended x-ray absorption fine-structure measurements. An anomalous upturn of the mean-square relative displacement of the Fe-As bond is detected below ∼70 K as electron carriers are introduced, reflecting the occurrence of Fe-As bond local lattice fluctuation. Similar to that in cuprates, this lattice fluctuation exhibits an abrupt depression at the onset superconducting transition temperature. The results indicate that strong electron-lattice interaction is involved in the superconducting transition in oxypcnictide superconductors, putting a strict limitation on possible theoretical models.
|ジャーナル||Physical Review B - Condensed Matter and Materials Physics|
|出版ステータス||Published - 2008 12月 1|
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