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TT: Fachverband Tiefe Temperaturen

TT 39: Focused Session: Frontiers of Electronic Structure Theory 4 (jointly with HL and O)

TT 39.7: Vortrag

Mittwoch, 13. März 2013, 12:15–12:30, H36

Structure, charge order, phonons and IR spectra of magnetite — •Charles Patterson — School of Physics, Trinity College Dublin, Dublin 2, Ireland.

The structure and charge order of magnetite (Fe₃O₄) below the Verwey transition have been contentious issues for over 70 years. An x-ray refinement for the full 112 atom, Cc space group crystal structure of magnetite was reported only recently [1]. Previous refinements were hampered by multiple domain twinning in samples, whereas the recent study was performed on a micron-sized sample with two domains. Here we report hybrid density functional theory (DFT) calculations for the crystal structure, charge order, vibrations and IR spectra of magnetite in the Cc (112 atom) and P2/c (56 atom) unit cells. Charge order in the Cc structure is found to consist of Fe trimerons, both in experiment [1] and calculations.

[1] M. S. Senn, J. P. Wright and J. P. Attfield, Nature 481, 173 (2012).