title: Nanoscale Origin of Mesoscale Roughening: Real-Time Tracking and Identification of Three Distinct Ruthenium Oxide Phases in Ruthenium Oxidation.
abstract: The structural modification of the Ru(0001) surface is followed in real-time using low-energy electron microscopy at elevated temperatures during exposure to molecular oxygen. We observe the nucleation and growth of three different RuO2 facets, which are unambiguously identified by single-domain microspot low-energy electron diffraction (μLEED) analysis from regions of 250 nm in diameter. Structural identification is then pushed to the true nanoscale by employing very-low-energy electron reflectivity spectra R(E) from regions down to 10 nm for structural fingerprinting of complex reactions such as the oxidation of metal surfaces. Calculations of R(E) with an ab initio scattering theory confirm the growth of (110), (100), and (101) orientations of RuO2 and explain the shape of the R(E) spectra in terms of the conducting band structure. This methodology is ideally suited to identify the structure of supported ultrathin films and dynamic transformations at multicomponent interfaces down to few nanometer lateral resolution at elevated temperature and in reactive environments.
authors.affiliation: Institute of Solid State Physics, University of Bremen , Otto-Hahn-Allee 1, 28359 Bremen, Germany.
authors.forename: Jan Ingo
authors.initials: JI
authors.lastname: Flege
authors.affiliation: Department of Physical Chemistry, Justus-Liebig-University , Heinrich-Buff-Ring 58, 35392 Gießen, Germany.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Herd
authors.affiliation: Department of Physical Chemistry, Justus-Liebig-University , Heinrich-Buff-Ring 58, 35392 Gießen, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Goritzka
authors.affiliation: Department of Physical Chemistry, Justus-Liebig-University , Heinrich-Buff-Ring 58, 35392 Gießen, Germany.
authors.forename: Herbert
authors.initials: H
authors.lastname: Over
authors.affiliation: Departamento de Física de Materiales, Universidad del Pais Vasco UPV/EHU , 20080 San Sebastián/Donostia, Basque Country, Spain.|Donostia International Physics Center (DIPC) , 20018 San Sebastián/Donostia, Basque Country, Spain.|IKERBASQUE, Basque Foundation for Science , 48011 Bilbao, Spain.
authors.forename: Eugene E
authors.initials: EE
authors.lastname: Krasovskii
authors.affiliation: Institute of Solid State Physics, University of Bremen , Otto-Hahn-Allee 1, 28359 Bremen, Germany.|MAPEX Center for Materials and Processes, University of Bremen , 28359 Bremen, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Falta
keywords: augmented plane wave method; in situ methods; low-energy electron microscopy and diffraction; ruthenium; transition metal oxidation