A novel mechanism to reduce coercive field of ferroelectric materials via {1 1 1} twin engineering

<p>Fig. 1. Comparison of polarization directions between untwinned structures and twinned structures. Two unit cells in (a) untwinned structure and (b) twinned structure are sketched in the upper panel. Projection of the polarization of (c) untwinned structure and (d) twinned structure on plane are illustrated in the lower panel. P, P1 and P2 denote polarizations, and Pp denotes the projected polarization on plane. Green, white and red balls stand for of Ba, Ti, and O, respectively. In projection view of (c) and (d), Ba atom columns stand for the Ba–O overlapped columns, which is consistent with the TEM images due to the relative weak reflection strength of oxygen atoms.