Berlin 2012 – scientific programme
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O: Fachverband Oberflächenphysik
O 4: Graphene I
O 4.3: Talk
Monday, March 26, 2012, 11:00–11:15, MA 041
Direct observation of electron confinement in epitaxial graphene nanoislands — Soo-Hyon Phark1, Jerome Borme1,2, •Augusto Leon Vanegas1, Marco Corbetta1, Dirk Sander1, and Jürgen Kirschner1 — 1Max Planck Institute of Microstructure Physics, Weingerg 2, 06120 Halle, Germany — 2International Iberian Nanotechnology laboratory, Avenida Mestre Jose Veiga, 4715-310 Braga, Portugal
A central question for the future applications of graphene is how the substrate and the lateral confinement of a graphene island affect the electronic properties. In this work we have used scanning tunneling spectroscopy to measure the differential conductance dI/dV of the graphene nanoisland deposited on Ir(111)[1]. The dI/dV maps show a spatial modulation, which depends on energy. We ascribe this spatial modulation of the local density of states to quantum confinement. An analysis of the energy dependence of these modulations gives a linear dispersion relation, E=E0± ℏ vF|k→| with E0=−90± 20 meV and a Fermi velocity vF=(6.0± 0.4)× 105 m/s. These findings are discussed in view of recently publish data [2,3].
[1] Soo-Hyon Phark, et al., ACS Nano, 2011, 5 (10), pp 8162-8166.
[2] S. Rusponi, et al., Phys. Rev. Lett. 105 (2010) 246803.
[3] M. Kralj et al., Phys. Rev. B 84, 075427 (2007).