Temperature-dependent local structure of LaFeAsO1-xF x: Probing the atomic correlations

Document Type

Article

Publication Date

12-15-2010

Abstract

The local structure of the parent and doped LaFeAsO1-xF x(pnictide) compounds were studied by x-ray absorption spectroscopy and density functional methods. In the doped system, the Fe-As and Fe-Fe correlations are both well modeled by an Einstein model. For the Fe-As bonds, the Einstein temperatures are identical for the doped (11%) and undoped samples but the doped sample is found to have a lower level of static disorder. Doping is found to increases the effective Einstein temperature of Fe-Fe atomic correlation. The results suggest that the onset of superconductivity in the F doped system may be related to enhanced magnetic interactions. Density functional calculations of the total charge density reveal strong bonding between neighboring As ions but metal-like behavior in the Fe layers. It is also seen directly that the replacement of oxygen by fluorine modifies the electron charge density mainly on the Fe sites. © 2010 American Institute of Physics.

Identifier

78650879114 (Scopus)

Publication Title

Journal of Applied Physics

External Full Text Location

https://doi.org/10.1063/1.3525999

ISSN

00218979

Issue

12

Volume

108

Grant

DE-FG02-07ER46402

Fund Ref

U.S. Department of Energy

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