When 10:30 AM - 11:30 AM Nov 09, 2018
Where 1571 G.G. Brown
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Embedding Metal Nanoparticles Beneath the Surface of a Layered Material


Patricia A. Thiel
Departments of Chemistry and Materials Science & Engineering, Iowa State University

There is currently great interest in exotic electronic states in quantum materials, including those derived from layered materials. Layered materials consist of weakly-coupled sheets, such as the graphene layers in graphite. In such materials, intercalation (insertion of a foreign material between the layers) is often feasible and is a well-known method for altering bulk properties. 

In this work, we have investigated intercalation of elemental metals at the surfaceof graphite, as a possible means of altering the surfaceproperties of graphite. We have found that under normal conditions there is no surface intercalation of transition metals or rare earths, but we have discovered conditions under which surface intercalation doesoccur for a wide variety of metals at the surface of graphite. This method may be applicable to other 2D materials or other configurations of 2D materials. Furthermore, the resultant structures are unexpected: The intercalated metals form multilayer nanoscale islands, rather than the dilute atomic layers typical of bulk intercalation. These islands are usually faceted, and for some metals, the island surface exhibits a moiré pattern that reflects a coincidence lattice between the top graphene and the underlying metal. Both features indicate good atomic order in the metal islands. Examples will be presented for Dy, Ru and Cu. Density functional theory sheds light on the driving force for intercalation, yielding a surprising result.

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