Orbital ordering and bond dimerization in magnetite Fe3O4

A new mechanism of the Verway transition in magnetite (Fe3O4) is proposed. It is argued to be a bond dimerization transition due to the interplay between the strong inter-orbital on-site Coulomb interaction on the Fe sites stabilizing a ferro-orbital ordered state making the system one-dimensional, and the electron-phonon interaction which results in the Peierls lattice distortion. Furthermore, discussions on the total elastic energy of the lattice lead us to a complicated lattice distortion pattern with large unit cell size in accordance with the experiments. (C) 2002 Elsevier Science B.V. All rights reserved.