Eur. Phys. J. B 69, 351-355 (2009)
https://doi.org/10.1140/epjb/e2009-00142-3

Symmetry of standing waves generated by a point defect in epitaxial graphene

¹ Laboratoire de Physique et de Spectroscopie Électronique, CNRS-UMR 7014, 4 rue des Frères Lumière, 68093 Mulhouse, France
² Institut de Physique Théorique, CEA/Saclay, CNRS-URA 2306, Orme des Merisiers, 91191 Gif-sur-Yvette, France

Corresponding author: ^a laurent.simon@uha.fr

Received: 3 December 2008
Revised: 25 March 2009
Published online: 29 April 2009

Abstract

Using scanning tunneling microscopy (STM) and Fourier Transform STM (FT-STM), we have studied a point defect in epitaxial graphene grown on silicon carbide substrate. We find a strong threefold anisotropy in the standing waves generated by the defect. We discuss possible relations between this anisotropy and the chirality of the electrons, and how it allows us to identify the position of the impurity. We extract the quasiparticle energy dispersion, and give a first experimental proof of the validity of Fermi liquid theory in graphene for a wide range of energies from -800 meV to +800 meV. All experimental measurements are compared and related to theoretical T-matrix calculations.