Element‐specific displacements in defect‐enriched TiO 2 : Indication of a flash sintering mechanism

Flash sintering experiments of ceramics indicate the formation of a state far from equilibrium. It is hypothesized that this state is enriched by Frenkel defects. The possibility is investigated that such lattice defects are being generated by a proliferation of lattice vibrations that lie close to the Brillouin zone edge. We show by means of Molecular Dynamics simulations of rutile TiO 2 that this mechanism generates Frenkel defects in concentrations far beyond equilibrium. These defects deform the whole lattice in a way that the mean‐square displacements of the vibration amplitudes of the Ti and O atoms are specifically enhanced. This finding compares well to atomic displacement data of flash sintered rutile TiO 2 reported recently.