Universität zu Köln

Martinez-Galera, A. J., Schroeder, U. A., Huttmann, F., Jolie, W., Craes, F., Busse, C., Caciuc, V., Atodiresei, N., Bluegel, S. and Michely, T. (2016). Oxygen orders differently under graphene: new superstructures on Ir(111). Nanoscale, 8 (4). S. 1932 - 1944. CAMBRIDGE: ROYAL SOC CHEMISTRY. ISSN 2040-3372

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Abstract

Using scanning tunneling microscopy, the oxygen adsorbate superstructures on bare Ir(111) are identified and compared to the ones formed by intercalation in between graphene and the Ir(111) substrate. For bare Ir(111) we observe O-(2 x 2) and O-(2 x 1) structures, thereby clarifying a persistent uncertainty about the existence of these structures and the role of defects for their stability. For the case of graphene-covered Ir(111), oxygen intercalation superstructures can be imaged through the graphene monolayer by choosing proper tunneling conditions. Depending on the pressure, temperature and duration of O-2 exposure as well as on the graphene morphology, O-(2 x 2), O-(root 3x root 3)-R30 degrees, O-(2 x 1) and O-(2 root 3 x 2 root 3)-R30 degrees superstructures with respect to Ir(111) are observed under the graphene cover. Two of these structures, the O-(root 3 x root 3)-R30 degrees and the (2 root 3 x 2 root 3)-R30 degrees structure are only observed when the graphene layer is on top. Phase coexistence and formation conditions of the intercalation structures between graphene and Ir(111) are analyzed. The experimental results are compared to density functional theory calculations including dispersive forces. The existence of these phases under graphene and their absence on bare Ir(111) are discussed in terms of possible changes in the adsorbate-substrate interaction due to the presence of the graphene cover.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Martinez-Galera, A. J. UNSPECIFIED UNSPECIFIED UNSPECIFIED Schroeder, U. A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Huttmann, F. UNSPECIFIED UNSPECIFIED UNSPECIFIED Jolie, W. UNSPECIFIED UNSPECIFIED UNSPECIFIED Craes, F. UNSPECIFIED UNSPECIFIED UNSPECIFIED Busse, C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Caciuc, V. UNSPECIFIED UNSPECIFIED UNSPECIFIED Atodiresei, N. UNSPECIFIED UNSPECIFIED UNSPECIFIED Bluegel, S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Michely, T. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-291583
DOI:	10.1039/c5nr04976h
Journal or Publication Title:	Nanoscale
Volume:	8
Number:	4
Page Range:	S. 1932 - 1944
Date:	2016
Publisher:	ROYAL SOC CHEMISTRY
Place of Publication:	CAMBRIDGE
ISSN:	2040-3372
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language SCANNING TUNNELING MICROSCOPE; AUGER-ELECTRON-SPECTROSCOPY; IRIDIUM 111 SURFACE; INDUCED RECONSTRUCTION; METAL-SURFACES; ADSORPTION; CHEMISORPTION; PT(111); INTERCALATION; KINETICS Multiple languages Chemistry, Multidisciplinary; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/29158