Regensburg 2013 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 12: Poster Session Superconductivity
TT 12.26: Poster
Montag, 11. März 2013, 15:00–19:00, Poster D
Evolution of the multiband RKKY interaction: Application to iron pnictides and chalcogenides — •Alireza Akbari1, Peter Thalmeier1, and Ilya Eremin2 — 1Max Planck Institute for the Chemical Physics of Solids, 01187 Dresden, Germany — 2Theoretische Physik III, Ruhr-Universität Bochum, 44780, Bochum, Germany
The indirect RKKY interaction in iron pnictide and chalcogenide metals is calculated for
a simplified four bands Fermi surface (FS) model. We investigate the specific multi-band features
and show that distinct length scales of the RKKY oscillations appear.
In the paramagnetic state the interaction is spin isotropic however, in the spin density wave (SDW) phases, the RKKY interaction maps into an effective anisotropic XXZ-type Heisenberg exchange model. The anisotropy originates from the breaking of the spin-rotational symmetry induced by the SDW order and its strength depends on the size of the SDW- gap and the structure of the folded Fermi surface.
For the regular lattice of the local moments, the generalized RKKY interaction is defined in momentum space.
We consider its momentum dependence in paramagnetic and SDW phases, discuss its implications for the possible type of magnetic order and compare
it to the results obtained from more realistic tight-binding type Fermi surface model.
Our finding can give important clues on the magnetic ordering of the 4f- iron based superconductors.
[1] A. Akbari, I. Eremin, and P. Thalmeier, Phys. Rev. B 84, 134513 (2011)
A. Akbari, P. Thalmeier, and I. Eremin (Preprint)