Dresden 2017 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 95: Metal Substrates: Adsorption of Atoms and Inorganic Molecules

O 95.2: Vortrag

Donnerstag, 23. März 2017, 15:30–15:45, WIL A317

Site-specific adsorption of heavy-metal atoms on corrugated graphene: A challenge for first-principles theory — •Georg S. Michelitsch and Karsten Reuter — Technische Universität München

Single, heavy-metal atoms are an appealing ultimate unit in the quest for an ever more miniaturized information storage. Adsorption on corrugated single-layer graphene could thereby protect the magnetic encoding and act as a template for self-assembly. Quantitative first-principles calculations would be a much desired source for independent insight into the geometric, electronic and magnetic properties of such systems. Unfortunately, they are challenged by the prerequisite to accurately describe the localized spin structure on the heavy-metal adsorbate simultaneously with the Moiré superstructure of the extended support. To this end we present systematic density-functional theory (DFT) calculations addressing the adsorption of Dy atoms on corrugated graphene. We compare treatments on the screened hybrid functional with the Hubbard-corrected (DFT+U) level, and discuss approaches to reach electronic self-consistency in this delicate system. The calculations reveal intricate consequenes of minor changes in electronic level alignment and state occupation on the preferred adsorption site. This calls for judicious choice and scrutiny of the employed U value in the numerically more efficient DFT+U approach.