Charge order and spin-singlet pair formation in Ti4O7

I. Leonov, A. N. Yaresko, V. N. Antonov, U. Schwingenschlögl, V. Eyert, V. I. Anisimov

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40 Citations (Scopus)

Abstract

Charge ordering in the low-temperature triclinic structure of titanium oxide (Ti4O7) is investigated using the local density approximation (LDA)+U method. Although the total 3d charge separation is rather small, an orbital order parameter defined as the difference between t 2g occupancies of Ti3+ and Ti4+ cations is large and gives direct evidence for charge ordering. Strong covalency of O2p-Ti3d σ-type bonds, which results in partial occupation of Ti e g states, leads to almost complete loss of the disproportionation between the charges at 3+and 4+Ti sites. The occupied t2g states of Ti3+ cations are predominantly of dxy character and form a spin-singlet molecular orbital via strong direct antiferromagnetic exchange coupling between neighbouring Ti(1) and Ti(3) sites, whereas the role of superexchange is found to be negligible.

Original languageEnglish
Article number022
Pages (from-to)10955-10964
Number of pages10
JournalJournal of Physics Condensed Matter
Volume18
Issue number48
DOIs
Publication statusPublished - 6 Dec 2006
Externally publishedYes

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