Polarization dependent chemistry of ferroelectric BaTiO3(001) domains

Recent works suggest that the surface chemistry, in particular the presence of oxygen vacancies, can affect the polarization in a ferroelectric material. This should, in turn, influence the domain ordering driven by the need to screen the depolarizing field. Here we show using density-functional theory that the presence of oxygen vacancies at the surface of BaTiO3(001) preferentially stabilizes an inward pointing, P-, polarization. Mirror electron microscopy measurements of the domain ordering confirm the theoretical results. (paper)