Orbital ordering in manganites in the band approach

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.

arXiv comment4 pages, 2 figures

References in corpus (6)

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• Double-exchange via degenerate orbitals
• Double-exchange model: phase separation versus canted spins
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• The Effect of Disorder in an Orbitally Ordered Jahn-Teller Insulator
• Orbital ordering in undoped manganites via a generalized Peierls instability
• Charge order induced in an orbital density-wave state
• Fermi surface nesting and possibility of orbital ordering in FeO