Microscopic origin of the linear temperature increase of the magnetic susceptibility of BaFe2As2

Abstract

Employing a combination of ab initio band-structure theory and dynamical mean-field theory we explain the experimentally observed linear temperature increase of the magnetic susceptibility of the iron pnictide material BaFe 2As 2. The microscopic origin of this anomalous behavior is traced to a sharp peak in the spectral function located approximately 100 meV below the Fermi level. This peak is due to the weak dispersion of two-dimensional bands associated with the layered crystal structure of pnictides. © 2012 American Physical Society.