title: Atomic-scale compensation phenomena at polar interfaces.
abstract: The interfacial screening charge that arises to compensate electric fields of dielectric or ferroelectric thin films is now recognized as the most important factor in determining the capacitance or polarization of ultrathin ferroelectrics. Here we investigate using aberration-corrected electron microscopy and density-functional theory to show how interfaces cope with the need to terminate ferroelectric polarization. In one case, we show evidence for ionic screening, which has been predicted by theory but never observed. For a ferroelectric film on an insulating substrate, we found that compensation can be mediated by an interfacial charge generated, for example, by oxygen vacancies.
authors.affiliation: Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA. chisholmmf@ornl.gov
authors.forename: Matthew F
authors.initials: MF
authors.lastname: Chisholm
authors.forename: Weidong
authors.initials: W
authors.lastname: Luo
authors.forename: Mark P
authors.initials: MP
authors.lastname: Oxley
authors.forename: Sokrates T
authors.initials: ST
authors.lastname: Pantelides
authors.forename: Ho Nyung
authors.initials: HN
authors.lastname: Lee