Electronic Band Dispersion of Graphene Nanoribbons via   Fourier-Transformed Scanning Tunneling Spectroscopy
  Atomically precise armchair graphene nanoribbons of width $N=7$ (7-AGNRs) are investigated by scanning tunneling spectroscopy (STS) on Au(111). The analysis of energy-dependent standing wave patterns of finite length ribbons allows, by Fourier transformation, the direct extraction of the dispersion relation of frontier electronic states. Aided by density functional theory calculations, we assign the states to the valence band, the conduction band and the next empty band of 7-AGNRs, determine effective masses of $0.42\pm 0.08\,m_e$, $0.40\pm 0.18\,m_e$ and $0.20\pm 0.03\,m_e$, respectively, and a band gap of $2.37\pm 0.06$ eV. 
Hajo S\"ode, Leopold Talirz, Oliver Gr\"oning, Carlo Antonio   Pignedoli, Reinhard Berger, Xinliang Feng, Klaus M\"ullen, Ro...
cond-mat.mes-hall