منابع مشابه
Orbital Ordering and Orbital Fluctuations in Transition Metal Oxides
We summarize some characteristic features of the frustrated magnetic interactions in spin-orbital models adequate for cubic transition metal oxides with orbital degeneracy. A generic tendency towards dimerization, found already in the degenerate Hubbard model, is confirmed for t2g but not for eg systems. In the t2g case the quantum orbital fluctuations are more pronounced and contribute to a st...
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Temperature-dependent dc susceptibility and x-ray powder diffraction on a pure tetragonal sample of Sr(2)VO(4) show an antiferromagnetic orbital-ordering transition at T(oo) = 97 K, in which the occupied orbitals lie along the c axis. The unusual broadening of the x-ray Bragg peaks throughout the orbital-ordering transition temperature region indicates that this process occurs in stages, and th...
متن کاملTheory of Orbital Ordering . II
According to the two-band model in the previous theory, the spontaneous magnetic moment due to the orbital motion of electrons in solids points to a special direction given by the interband matrix element of the angular momentum of an electron around the lattice site to which it belongs. For the three-fold degenerate bands, the free energy of the system is shown to be independent of the directi...
متن کاملOn charge and orbital ordering in La0.5Sr1.5MnO4
Using first principle band structure calculations, we critically examine results of resonant x-ray scattering experiments which is believed to directly probe charge and orbital ordering. Considering the specific case of La0.5Sr1.5MnO4, we show that this technique actually probes most directly and sensitively small structural distortions in the system. Such distortions, often difficult to detect...
متن کاملOrbital ordering in paramagnetic LaMnO3 and KCuF3
Ab initio studies of the stability of orbital ordering, its coupling to magnetic structure and its possible origins ~electron-phonon and/or electron-electron interactions! are reported for two perovskite systems, LaMnO3 and KCuF3. We present an average spin state calculational scheme that allowed us to treat a paramagnetic state and to succesfully describe the experimental magnetic or orbital p...
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ژورنال
عنوان ژورنال: Journal of Physics A: Mathematical and General
سال: 2003
ISSN: 0305-4470,1361-6447
DOI: 10.1088/0305-4470/36/35/307