title: Low-temperature resistance anomaly at SrTiO3 grain boundaries: evidence for an interface-induced phase transition.
abstract: Variable temperature transport between 1.4 and 300 K, structural imaging, and theoretical calculations were used to characterize the properties of electrically active 24 degrees and 36.8 degrees [001] tilt SrTiO3 grain boundaries with 0.1 at. % niobium doping. An anomaly in boundary resistance and capacitance characteristics typical of a positive temperature coefficient effect is observed. This behavior is indicative of interface-induced dipole ordering. The detailed atomic structures of these grain boundaries were determined from a comparison of ab initio calculations and Z-contrast TEM images. The number of excess electrons at the boundaries determined experimentally and theoretically agrees and is associated with the boundary structural units.
authors.affiliation: Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Rui
authors.initials: R
authors.lastname: Shao
authors.forename: Matthew F
authors.initials: MF
authors.lastname: Chisholm
authors.forename: Gerd
authors.initials: G
authors.lastname: Duscher
authors.forename: Dawn A
authors.initials: DA
authors.lastname: Bonnell