Role of local geometry in the spin and orbital structure of transition metal compounds
| Autor: | A. O. Sboychakov, Sergey V. Streltsov, K. I. Kugel, D. I. Khomskii |
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| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
Angular momentum
LOCAL GEOMETRY Solid-state physics ORBITAL INTERACTION FOS: Physical sciences General Physics and Astronomy Geometry 02 engineering and technology ORBIT COUPLING 01 natural sciences OXYGEN Condensed Matter - Strongly Correlated Electrons Transition metal DIFFERENT GEOMETRY 0103 physical sciences ORBITAL DEGENERACY TRANSITION METAL COMPOUNDS 010306 general physics Spin (physics) Physics Coupling Strongly Correlated Electrons (cond-mat.str-el) GEOMETRY TRANSITION METALS ORBITAL ORDER 021001 nanoscience & nanotechnology Octahedron Condensed Matter::Strongly Correlated Electrons METALS Symmetry (geometry) 0210 nano-technology Degeneracy (mathematics) REAL SYSTEMS SPIN COUPLINGS |
| Zdroj: | J. Exp. Theor. Phys. Journal of Experimental and Theoretical Physics |
| Popis: | We analyze the role of local geometry in the spin and orbital interaction in transition metal compounds with orbital degeneracy. We stress that the tendency observed for the most studied case (transition metals in O$_6$ octahedra with one common oxygen -- common corner of neighboring octahedra and with $\sim 180^{\circ}$ metal--oxygen--metal bonds), that ferro-orbital ordering renders antiferro-spin coupling, and, {\it vice versa}, antiferro-orbitals give ferro-spin ordering, is not valid in general case, in particular for octahedra with common edge and with $\sim 90^{\circ}$ M--O--M bonds. Special attention is paid to the ``third case'', neighboring octahedra with common face (three common oxygens) -- the case practically not considered until now, although there are many real systems with this geometry. Interestingly enough, the spin--orbital exchange in this case turns out to be to be simpler and more symmetric than in the first two cases. We also consider, which form the effective exchange takes for different geometries in case of strong spin--orbit coupling. Comment: 31 pages, 9 figures, submitted to JETP |
| Databáze: | OpenAIRE |
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