Structure and ordering of oxygen on unreconstructed Ir(100)

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Details zur Publikation

Autorinnen und Autoren: Ferstl P, Schmitt T, Schneider MA, Hammer L, Michl A, Mueller S
Zeitschrift: Physical Review B
Verlag: AMER PHYSICAL SOC
Jahr der Veröffentlichung: 2016
Band: 93
Heftnummer: 23
ISSN: 2469-9950
Sprache: Englisch


Abstract


The adsorption of oxygen on the unreconstructed Ir(100) surface is investigated by a combination of experimental and theoretical methods comprising low-energy electron diffraction (LEED), scanning tunneling microscopy (STM), and density-functional theory (DFT). Apart from the well-known (2 x 1)-O phase, we find a new (3 x 1)-O phase for temperatures below 180 K. Our DFT calculations predict these two phases to be the only fundamental ground states of the system in the coverage range up to 0.5 monolayers. An analysis of the phase transitions as a function of coverage reveals extended coexistence ranges between the clean surface and the 3 x 1 phase, or between the 3 x 1 and 2 x 1 phases, respectively. As a function of temperature, both phases undergo order-disorder transitions at about 650 K for the 2 x 1 phase and 180 K for the 3 x 1 phase, the latter being only partially reversible. The complete ordering behavior can be consistently explained by the energetics of model defect structures calculated by DFT. The crystallographic structure of the phases is determined by full-dynamical LEED intensity analyses, yielding excellent agreement between experimental and calculated data sets (Pendry R-factors: R-P approximate to 0.1). Oxygen was found to assume bridge sites always inducing significant relaxations within the substrate. The derived structural parameters coincide with the respective predictions from DFT on the picometer scale. It is also shown that remnants and precursor stages of the clean surface's reconstruction can only be detected through the application of real-space methods such as STM. The overarching objective of the present study is to demonstrate how precisely and accurately such an adsorption system can be investigated nowadays by using a concerted experimental and theoretical approach.



FAU-Autorinnen und Autoren / FAU-Herausgeberinnen und Herausgeber

Ferstl, Pascal
Professur für Experimentalphysik
Hammer, Lutz Dr.
Lehrstuhl für Festkörperphysik
Schneider, M. Alexander Prof. Dr.
Professur für Experimentalphysik


Einrichtungen weiterer Autorinnen und Autoren

Technische Universität Hamburg-Harburg (TUHH)


Zitierweisen

APA:
Ferstl, P., Schmitt, T., Schneider, M.A., Hammer, L., Michl, A., & Mueller, S. (2016). Structure and ordering of oxygen on unreconstructed Ir(100). Physical Review B, 93(23). https://dx.doi.org/10.1103/PhysRevB.93.235406

MLA:
Ferstl, Pascal, et al. "Structure and ordering of oxygen on unreconstructed Ir(100)." Physical Review B 93.23 (2016).

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