Role of the Pinning Points in epitaxial Graphene Moiré Superstructures on the Pt(111) Surface

Abstract

The intrinsic atomic mechanisms responsible for electronic doping of epitaxial graphene Moirés on transition metal surfaces is still an open issue. To better understand this process we have carried out a first-principles full characterization of the most representative Moiré superstructures observed on the Gr/Pt(111) system and confronted the results with atomically resolved scanning tunneling microscopy experiments. We find that for all reported Moirés the system relaxes inducing a non-negligible atomic corrugation both, at the graphene and at the outermost platinum layer. Interestingly, a mirror “anti-Moiré” reconstruction appears at the substrate, giving rise to the appearance of pinning-points. We show that these points are responsible for the development of the superstructure, while charge from the Pt substrate is injected into the graphene, inducing a local n-doping, mostly localized at these specific pinning-point positions.

Influence of interface interaction on the moiré superstructures of graphene on transition-metal substrates

“…Even for the weak van der Waals interacting Pt(111) substrate, a recent study indicated that at the pinning-points, migration of the electronic charges from the s towards the d z 2 orbitals in the Pt atoms increases the orbital directionality, facilitating the hybridization with the p z orbitals of the buckled graphene C atoms. 29 By the proper selection and control of the interfacial interaction between graphene and the transition-metal substrate, a variety of moiré superstructures could be synthesized to meet the requirements of the practical applications.…”

Chemical Changes of Graphene Oxide Thin Films Induced by Thermal Treatment under Vacuum Conditions

“…Among the family of graphene materials, graphene oxide (GO) as well as reduced graphene oxide (rGO) seem to be better positioned than pristine graphene for industrial applications. This is because of some of their chemical methods are well established for synthesizing bulk quantities of GO [3][4][5] and rGO [5][6][7], while it is much more complex to obtain pristine graphene [8][9][10][11].…”

“…Nevertheless, these methods have several drawbacks that limit the potential applications of the obtained material. The GO flakes produced by these methods usually have uneven shapes, with a thickness of a few layers and a maximum lateral size of few microns [5][6][7][8][9][10][11][12]. The preparation of thin films or paper-like GO by stacking GO flakes [13][14][15][16] is a good approach for partially overtaking the above-mentioned limitations.…”

Atomically-resolved edge states on surface-nanotemplated graphene explored at room temperature

“…The E F of our sample is slightly shifted towards negative bias (7 mV) with respect to the absolute zero measured by our microscope. 32 In Fig. 4 we present five current error maps of the same region for increasing bias voltage.…”

“…Both terraces are covered with graphene presenting a (√7 × √7)R19°moiré superstructure (see the lower right inset for details of the moiré). 31,32 At the relative high voltage bias (400 mV) used to measure Fig. 1b, the graphene discontinuity between both terraces is clearly visible as a stripe of amorphous configuration in the middle of the image.…”