title: Tracking the Verwey Transition in Single Magnetite Nanocrystals by Variable-Temperature Scanning Tunneling Microscopy.
abstract: Variable-temperature scanning tunneling spectroscopy revealed a sharp Verwey transition in individual ∼10 nm magnetite nanocrystals prepared by the coprecipitation technique and embedded in the surface of a gold film. The transition was observed as a significant change in the electronic structure around the Fermi level, with an apparent band gap of ∼140-250 meV appearing below the transition temperature and a pseudogap of ∼75 ± 10 meV appearing above it. The transition temperature was invariably observed around 101 ± 2 K for different nanocrystals, as opposed to 123 K typically reported for stoichiometric bulk crystals. This suggests that the lowering of the transition temperature is an intrinsic finite size effect, probably due to the presence of the surface.
authors.affiliation: School of Chemistry and Center for Nanoscience and Nanotechnology, Tel Aviv University , Tel Aviv 69978, Israel.
authors.forename: Amir
authors.initials: A
authors.lastname: Hevroni
authors.affiliation: Department of Physics, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States.
authors.forename: Mukund
authors.initials: M
authors.lastname: Bapna
authors.affiliation: Department of Physics, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States.
authors.forename: Stephan
authors.initials: S
authors.lastname: Piotrowski
authors.affiliation: Department of Physics, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States.
authors.forename: Sara A
authors.initials: SA
authors.lastname: Majetich
authors.affiliation: School of Chemistry and Center for Nanoscience and Nanotechnology, Tel Aviv University , Tel Aviv 69978, Israel.
authors.forename: Gil
authors.initials: G
authors.lastname: Markovich