title: Insulator at the ultrathin limit: MgO on Ag(001).
abstract: The electronic structure and morphology of ultrathin MgO films epitaxially grown on Ag(001) were investigated using low-temperature scanning tunneling spectroscopy and scanning tunneling microscopy. Layer-resolved differential conductance (dI/dU) measurements reveal that, even at a film thickness of three monolayers, a band gap of about 6 eV is formed corresponding to that of the MgO(001) single-crystal surface. This finding is confirmed by layer-resolved calculations of the local density of states based on density functional theory.
authors.affiliation: Institut de Physique de la Matière Condensée, Université de Lausanne, CH-1015 Lausanne, Switzerland.
authors.forename: S
authors.initials: S
authors.lastname: Schintke
authors.forename: S
authors.initials: S
authors.lastname: Messerli
authors.forename: M
authors.initials: M
authors.lastname: Pivetta
authors.forename: F
authors.initials: F
authors.lastname: Patthey
authors.forename: L
authors.initials: L
authors.lastname: Libioulle
authors.forename: M
authors.initials: M
authors.lastname: Stengel
authors.forename: A
authors.initials: A
authors.lastname: De Vita
authors.forename: W D
authors.initials: WD
authors.lastname: Schneider