Observations of local electron states on the edges of the circular pits onhydrogen-etched graphite surface by scanning tunneling spectroscopy

scanning tunneling microscopy (STM) and spectroscopy (STS) are used to stud y electronic states at the edges of the circular pits on the hydrogen-etche d graphite surface. The edge surface state revealed by tunneling spectrosco py appears as the maximum of the local density of states (LDOS) in the ener gy range of 90-250 meV above the Fermi level. The dispersion of the energy state is explained by the band broadening in AB stacked H-terminated graphi te. The magnitude of the edge state decreases with the distance from the pi t edge as theoretically predicted. (C) 2000 Elsevier Science B.V. All right s reserved.