Sublattice Localized Electronic States in Atomically Resolved Graphene-Pt(111) Edge-Boundaries

Abstract

Understanding the connection of graphene with metal surfaces is a necessary step for developing atomically precise graphene-based technology. Combining high-resolution STM experiments and DFT calculations, we have unambiguously unveiled the atomic structure of the boundary between a graphene zigzag edge and a Pt(111) step. The graphene edges minimize their strain by inducing a 3-fold edge-reconstruction on the metal side. We show the existence of an unoccupied electronic state that is mostly localized on the C-edge atoms of one particular graphene sublattice, which could have implications in the design of graphene based devices.

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

“…Both STM topographic and current error maps show the same atomic scale features, but the latter present enhanced resolution. 36 When analyzing the absolute current error map obtained simultaneously with the topographic images at bias close to the Fermi level a striking effect shows up. Although restrictive feedback conditions were used to scan the highly faceted surface, the microscope could not keep the current setpoint when the tip scanned over the step-like graphene edges, leading to a high value of the current.…”

“…Such covalently bonded edges can, however, present sublattice-localized electronic states of moderate intensity if the graphene layer remains flat and is not combed like in the present case. 36 To enhance the resolution of the images, we have recorded quasi-constant height STM images. In this mode, we represent current error maps where the difference between the current setpoint and the measured current for every pixel during conventional STM operations with feedback conditions "on" is plotted.…”

Graphene quantum dots: wave function mapping by scanning tunneling spectroscopy and transport spectroscopy of quantum dots prepared by local anodic oxidation

“…They are induced by a gain in kinetic energy due to the formation of Clar's sextets in the bulk of graphene, which only become possible, if uncompensated π‐electrons are placed at any third edge atom of the zig‐zag edge, eventually forming the edge state . Experimental evidence for such edge states has indeed been found for graphene edges on different substrates such as HOPG , Si(100) , Au(111) , Cu(001), if the graphene is laterally interfaced with BN, , arguably Pt(111) , SiC(0001) , and SiO 2 . Spectroscopic features at the step edges of Ir(111) covered with graphene have also been interpreted in terms of graphene edge states , albeit it is known that the graphene layer is not interrupted at the Ir step edges .…”

Pt monatomic wire supported on graphene nanoribbon for oxygen reduction reaction

“…31,35 Recently, the atomic structure of the boundary between a graphene zigzag edge and a Pt(111) step has been unveiled by STM experiments and DFT calculation, which shows the strong bonding between the edge C and Pt atoms. 36 Thus, the synthesis of Pt monatomic wire that is supported on the zigzag edges of graphene nanoribbon (Pt-GNR) is feasible.…”

“…36 Thus, the corrugated Pt-GNR is considered in our work. The structure of Pt-GNR that is proposed in ref.…”