title: Interface-induced nonswitchable domains in ferroelectric thin films.
abstract: Engineering domains in ferroelectric thin films is crucial for realizing technological applications including non-volatile data storage and solar energy harvesting. Size and shape of domains strongly depend on the electrical and mechanical boundary conditions. Here we report the origin of nonswitchable polarization under external bias that leads to energetically unfavourable head-to-head domain walls in as-grown epitaxial PbZr(0.2)Ti(0.8)O3 thin films. By mapping electrostatic potentials and electric fields using off-axis electron holography and electron-beam-induced current with in situ electrical biasing in a transmission electron microscope, we show that electronic band bending across film/substrate interfaces locks local polarization direction and further produces unidirectional biasing fields, inducing nonswitchable domains near the interface. Presence of oxygen vacancies near the film surface, as revealed by electron-energy loss spectroscopy, stabilizes the charged domain walls. The formation of charged domain walls and nonswitchable domains reported in this study can be an origin for imprint and retention loss in ferroelectric thin films.
authors.affiliation: Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: Myung-Geun
authors.initials: MG
authors.lastname: Han
authors.affiliation: Department of Applied Physics and Center for Research on Interface Structures and Phenomena, Yale University, New Haven, Connecticut 06520, USA.
authors.forename: Matthew S J
authors.initials: MS
authors.lastname: Marshall
authors.affiliation: Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: Lijun
authors.initials: L
authors.lastname: Wu
authors.affiliation: Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: Marvin A
authors.initials: MA
authors.lastname: Schofield
authors.affiliation: JEOL USA Inc., Peabody, Massachusetts 01960, USA.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Aoki
authors.affiliation: Gatan Inc., Pleasanton, California 94588, USA.
authors.forename: Ray
authors.initials: R
authors.lastname: Twesten
authors.affiliation: Department of Applied Physics and Center for Research on Interface Structures and Phenomena, Yale University, New Haven, Connecticut 06520, USA.
authors.forename: Jason
authors.initials: J
authors.lastname: Hoffman
authors.affiliation: Department of Applied Physics and Center for Research on Interface Structures and Phenomena, Yale University, New Haven, Connecticut 06520, USA.
authors.forename: Frederick J
authors.initials: FJ
authors.lastname: Walker
authors.affiliation: Department of Applied Physics and Center for Research on Interface Structures and Phenomena, Yale University, New Haven, Connecticut 06520, USA.
authors.forename: Charles H
authors.initials: CH
authors.lastname: Ahn
authors.affiliation: Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: Yimei
authors.initials: Y
authors.lastname: Zhu