Berlin 2018 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 38: Theory of strongly correlated systems
MA 38.7: Vortrag
Donnerstag, 15. März 2018, 11:30–11:45, H 0110
Electronic structure and antiferromagnetism in a three-orbital model for iron pnictides. — •Sayandip Ghosh — Institute for Theoretical Physics, TU Dresden
The iron pnictides are the new class of high Tc superconductors after cuprates. They exhibit a rich temperature-doping phase diagram in which the parent compounds go through a structural transition and a magnetic phase transition to stripe antiferromagnetic (AFM) state. The electronic structure from first-principle techniques and ARPES experiments reveal two nearly circular hole pockets and two elliptical electron pockets. The magnetic excitations in the magnetic state examined by inelastic neutron scattering measurements yield well defined spin wave excitations with a maximum at the ferromagnetic zone boundary. Towards understanding the electronic and magnetic properties, we propose and investigate a three-orbital itinerant-electron model and show that essential features of electronic structure and magnetism can be understood in this model. We also demonstrate how the effective spin couplings are generated from particle-hole propagator explaining microscopic origin of ferromagnetic spin coupling along b direction required to understand spin wave dispersion.