Impurity scattering and size quantization effects in a single graphene nanoflake

Abstract

By using Fourier-transform scanning tunneling spectroscopy we measure the interference patterns produced by the impurity scattering of confined Dirac quasiparticles in epitaxial graphene nanoflakes. Upon comparison of the experimental results with tight-binding calculations of realistic model flakes, we show that the characteristic features observed in the Fourier-transformed local density of states are related to scattering between different transverse modes (sub-bands) of a graphene nanoflake and allow direct insight into the electronic spectrum of graphene. We also observe a strong reduction of quasiparticle lifetime which is attributed to the interaction with the underlying substrate. In addition, we show that the distribution of the onsite energies at flower defects leads to an effectively broken pseudospin selection rule, where intravalley back-scattering is allowed.

11 pages, 3 figures

References in corpus (13)

• Electric Field Effect in Atomically Thin Carbon Films
• The electronic properties of graphene
• Energy Gaps in Graphene Nanoribbons
• Half-Metallic Graphene Nanoribbons
• Emergence of magnetism in graphene materials and nanostructures
• Tailoring the atomic structure of graphene nanoribbons by STM lithography
• Scanning Tunneling Spectroscopy of Graphene on Graphite
• Etching and Narrowing of Graphene from the Edges
• Electron states of mono- and bilayer graphene on SiC probed by STM
• Grain Boundary Loops in Graphene
• Quasiparticle Chirality in Epitaxial Graphene Probed at the Nanometer Scale
• Effect of a single impurity on the local density of states in monolayer and bilayer graphene
• Role of pseudospin in quasiparticle interferences in epitaxial graphene probed by high-resolution scanning tunneling microscopy