2 research outputs found
Probing the Site-Dependent Kondo Response of Nanostructured Graphene with Organic Molecules
TCNQ
molecules are used as a sensitive probe for the Kondo response
of the electron gas of a nanostructured graphene grown on Ru(0001)
presenting a moiré pattern. All adsorbed molecules acquired
an extra electron by charge transfer from the substrate, but only
those adsorbed in the FCC-Top areas of the moiré show magnetic
moment and Kondo resonance in the STS spectra. DFT calculations trace
back this behavior to the existence of a surface resonance in the
low areas of the graphene moiré, whose density distribution
strongly depends on the stacking sequence of the moiré area
and effectively quenches the magnetic moment for HCP-Top sites
Elastic Response of Graphene Nanodomes
The mechanical behavior of a periodically buckled graphene membrane has been investigated by noncontact atomic force microscopy in ultrahigh vacuum. When a graphene monolayer is grown on Ru(0001), a regular arrangement of 0.075 nm high nanodomes forming a honeycomb lattice with 3 nm periodicity forms spontaneously. This structure responds in a perfectly reversible way to relative normal displacements up to 0.12 nm. Indeed, the elasticity of the nanodomes is proven by realistic DFT calculations, with an estimated normal stiffness <i>k</i> ∼ 40 N/m. Our observations extend previous results on macroscopic graphene samples and confirm that the elastic behavior of this material is maintained down to nanometer length scales, which is important for the development of new high-frequency (terahertz) electromechanical devices