Dresden 2011 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 32: SC: Fe-based Superconductors - Theory

TT 32.1: Vortrag

Mittwoch, 16. März 2011, 10:30–10:45, HSZ 304

Optical spectra and bandstructure in the SDW phase of the iron pnictides using density functional theory — •Johannes Ferber, Yu-Zhong Zhang, Kateryna Foyevtsova, Harald O. Jeschke, and Roser Valenti — Institut für Theoretische Physik, Goethe- Universität Frankfurt

Understanding the antiferromagnetic (SDW) phase of the iron pnictides is important as superconductivity in these systems arises from either doping or pressurizing the antiferromagnetic parent compounds. However, density functional calculations in these systems are known to largely overestimate the magnetic moments. In our calculations, we suppress the moments to reasonable values and analyse the optical conductivity and bandstructure, finding that a number of features observed in experiments can be reproduced in this way. In addition, we consider the effect of spin excitations on the optical conductivity. Whereas the static antiferromagnetic order is commonly taken into account in DFT calculations, spin flip terms which lead to spin excitations (magnons) are not considered. Using a high-quality tight-binding model, we include the coupling of the electrons to the magnons into the calculation of the optical conductivity.