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Orbital ordering in manganites in the band approach

D. V. Efremov·D. I. Khomskii
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Abstract

We consider the orbital ordering in LaMnO3 and similar systems, proceeding from the band picture. We show that for the realistic magnetic structure of A-type there exists a complete nesting betweeen two e_g-bands. As a result there occurs an instability towards an excitonic insulator-like state -- an electron-hole pairing with the wave vector Q=(π,π), which opens a gap in the spectrum and makes the system insulating. In the resulting state there appeasr an orbital ordering -- orbital density wave (ODW), the type of which coincides with those existing in LaMnO3.

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D. V. Efremov, D. I. Khomskii. 2004-07-25. Orbital ordering in manganites in the band approach. https://doi.org/10.1103/physrevb.72.012402

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