Spin-orbital frustrations and anomalous metallic state in iron-pnictide superconductors
By F. Kruger, Sanjeev Kumar, J. Zaanen, J. van den Brink. 2008
196 citations recorded by the source corpus.
We develop an understanding of the anomalous metal state of the parent compounds of recently discovered iron-based superconductors starting from a strong-coupling viewpoint, including orbital degrees of freedom. On the basis of an intermediate-spin (S=1) state for the Fe2+ ions, we derive a Kugel-Khomskii spin-orbital Hamiltonian for the active t2g orbitals. It turns out to be a highly complex model with frustrated spin and orbital interactions. We compute its classical phase diagrams and provide an understanding for the stability of the various phases by investigating its spin-only and orbital-only limits. The experimentally observed spin-stripe state is found to be stable over a wide regime of physical parameters and can be accompanied by three different types of orbital orders. Of these the orbital-ferro and orbital-stripe orders are particularly interesting since they break the in-plane lattice symmetry—a robust feature of the undoped compounds. We compute the magnetic excitation spectra for the effective spin Hamiltonian, observing a strong reduction in the ordered moment, and point out that the proposed orbital ordering pattern can be measured in resonant x-ray diffraction.
Subfields: Accounting, Condensed Matter Physics, Electronic, Optical and Magnetic Materials
View Paper: https://www.semanticscholar.org/paper/0f1d820ccf7374b31482c8fbccb8a0fbe7e7b7c4
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In Accounting
In Condensed Matter Physics
In Electronic, Optical and Magnetic Materials
Citations in the corpus
- In-plane electronic anisotropy of underdoped ‘122’ Fe-arsenide superconductors revealed by measurements of detwinned single crystals (2011, background): “We return to the significance of these observations in relation to the resistivity anisotropy in section 6.”