Striped antiferromagnetism and electronic structures of SrFeAsF and their implications

Institute of Physics, Chinese Academy of Sciences - Beijing 100190, China and Beijing National Laboratory for Condensed Matter Physics - Beijing 100190, China

Corresponding author: bgliu@mail.iphy.ac.cn

Received: 8 February 2009
Accepted: 3 March 2009

Abstract

We investigate structural, magnetic, and electronic properties of SrFeAsF as a new parent for superconductors using a state-of-the-art density-functional theory method. Calculated results show that the striped antiferromagnetic order is the magnetic ground state in the Fe layer and the interlayer magnetic interaction is tiny. Calculated As and Sr positions are in good agreement with experiment. There are only two quasi–two-dimensional bands near the Fermi level. The valence charge is mainly in the Fe and F layers, and the magnetic moment is confined to the Fe atoms. All the spin couplings within the Fe layer are antiferromagnetic due to the superexchange through the nearest As atoms. These results, with the record-equaling phase-transition temperature in the latest Sm-doped SrFeAsF, show that the SrFeAsF, sharing the same structure with LaFeAsO, is promising for achieving better superconductors.