Surface states on reconstructed diamond (111)

With the use of angle-resolved photoemission with synchrotron radiation, surface states on the (2×1)/(2×2) reconstructed diamond (111) surface are characterized. These states cover an energy range of about 2 eV and exhibit maximum emission intensity at 1 eV below the valence-band maximum in normal emission (i.e., at the center $\overline{\Gamma }$ of the surface Brillouin zone). The symmetry is determined to be ${\Lambda }_1(s,p_z-\mathrm{l}\mathrm{i}\mathrm{k}\mathrm{e})$ by using polarization selection rules. For off-normal emission an upwards energy dispersion by about 1 eV is seen. This behavior is similar to the energy position, dispersion, and symmetry of surface states on the Si(111)-(2×1) cleavage plane and in contrast with the momentum distribution of the $\pi$ band of graphite which is peaked at the boundary of the surface Brillouin zone.