Band antiferromagnetism in a two-band model for iron pnictides
Fachbereich Physik, Philipps Universität Marburg - Renthof 6, 35032 Marburg, Germany
Received: 6 March 2014
Accepted: 28 May 2014
In this work I investigate a two-band Hubbard model using the Gutzwiller wave function. The tight-binding part of the model was constructed to have a gapless spin-density wave state which leads to Dirac points in the bandstructure, a common feature of many iron-pnictide compounds. For quarter, half and three-quarter fillings I show that Hund's rule coupling has a large impact on the metal-insulator transition in the paramagnetic phase. For the half-filled model in the antiferromagnetic phase, the magnetism evolves in a Stoner-like behavior and the size of the ordered moment is mainly determined by the Hubbard interaction. As Hund's coupling plays a minor role in this state, the model does not describe Hund's metal which is in contrast to more realistic models for iron-pnictide compounds.
PACS: 71.27.+a – Strongly correlated electron systems; heavy fermions / 75.30.Fv – Spin-density waves / 71.30.+h – Metal-insulator transitions and other electronic transitions
© EPLA, 2014