Eur. Phys. J. B (2015) 88: 67
https://doi.org/10.1140/epjb/e2015-50780-7

Regular Article

Reduced iron ordered moment and negative T_C-pressure coefficient in iron-arsenide superconductors

Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, P.R. China

^a e-mail: liugq@nimte.ac.cn

Received: 5 November 2014
Received in final form: 8 January 2015
Published online: 19 March 2015

Abstract

The striped antiferromagnetic phase of iron-arsenides is investigated by the density functional calculations including Coulomb repulsion. Two low moment solutions with m ≈ 0.4 μ_B and m ≈ 1.0 μ_B have been found from calculations. The electronic structures indicate that the low moment states originate in the strong orbital hybridization between antiferromagnetic Fe neighbors. Therefore, the geometry of FeAs₄ tetrahedron, which is characterized by a parameter of h_As/a, is crucial to the low moment states. We show that the puzzling negative T_C-pressure coefficient of iron-arsenides can be consistently explained by the obtained low moment states.