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arXiv · 0906.0492

Ferroelectricity in multiferroic magnetite Fe3O4 driven by noncentrosymmetric Fe2+/Fe3+ charge-ordering: First-principles study

Kunihiko Yamauchi·Tetsuya Fukushima·Silvia Picozzi
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Abstract

By means of first-principles simulations, we unambiguously show that improper ferroelectricity in magnetite in the low-temperature insulating phase is driven by charge-ordering. An accurate comparison between monoclinic ferroelectric Cc and paraelectric P2/c structures shows that the polarization arises because of "shifts" of electronic charge between octahedral Fe sites, leading to a non-centrosymmetric Fe2+/Fe3+ charge-ordered pattern. Our predicted values for polarization, in good agreement with available experimental values, are discussed in terms of point-charge dipoles located on selected Fe tetrahedra, pointing to a manifest example of electronic ferroelectricity driven by charge rearrangement.

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Kunihiko Yamauchi, Tetsuya Fukushima, Silvia Picozzi. 2009-06-02. Ferroelectricity in multiferroic magnetite Fe3O4 driven by noncentrosymmetric Fe2+/Fe3+ charge-ordering: First-principles study. https://doi.org/10.1103/physrevb.79.212404

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