Plasmonic excitations and transport properties of graphene ribbons and dots

• Applicant: Professor Dr. Christoph Tegenkamp
• Subject Area: Experimental Condensed Matter Physics
• Term: from 2010 to 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 172373930

Nanostructuring of graphene opens the possibility to functionalize the originally gap-less 2D-graphene. Several fundamental physical aspects of nanostructured graphene will be in the focus of our efforts during this funding period: Besides wave guiding, which is an important issue for plasmonics, gap opening and edge channel states will be studied using appropriately designed nanostructures. Electronic transport properties and collective excitations in graphene nanostructures will be systematically studied as a function of ribbon width, geometry, adsorption of dopants including magnetic impurities, and as a function of temperature by means of 4-tip STM/SEM and angle resolved high resolution electron energy loss spectroscopy (EELS). As recently demonstrated, nanoribbon structures grown on appropriately designed SiC(0001)-MESA structures reveal an exceptional ballistic transport signature with extremely large elastic mean free path lengths (10 mu m at 300K). Using optical lithography, both the width and geometry of the ribbons will be systematically modified. Thus we want to gain controlled access to edge states, band gaps and electronic subbands. The route of processing even allows to grow large ensembles of identical nanostructures, so that spatially averaging techniques (ARPES, Raman, EELS) can be applied to complement STM/STS and local transport data. Intercalation with different adsorbates on various graphene supporting substrates will be studied intensely as a further important technique of functionalization. This technique facilitates studies of edge decoration in graphene nanostructures, in addition to shifts of the chemical potential and modified interaction with the substrate.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1459: Graphen
• Major Instrumentation: SPA-LEED System
• Instrumentation Group: 5160 Elektronenbeugungs-Apparaturen, LEED-, RHEED-, SHEED-Apparaturen
• Participating Person: Professor Dr. Herbert Pfnür