Charge Order in LuFe2O4: Antiferroelectric Ground State and Coupling to Magnetism

Abstract

X-ray scattering by multiferroic LuFe2O4 is reported. Below 320 K, superstructure reflections indicate an incommensurate charge order with propagation close to �1 3 1 3 3 2�. The corresponding charge configuration, also found by electronic structure calculations as most stable, contains polar Fe=O double layers with antiferroelectric stacking. Diffuse scattering at 360 K, with �1 3 1 3 0� propagation, indicates ferroelectric short-range correlations between neighboring double layers. The temperature dependence of the incommensuration indicates that charge order and magnetism are coupled.