PI-BONDED-TRIMER FORMATION ON THE CLEAN DIAMOND C(111) SURFACE

Using the local-orbital density-functional molecular-dynamics method, we have found a (2 x 2) pi-bonded-trimer structure, which has a slight ly lower total energy than that of Pandey's (2 x 1) pi-bonded-chain st ructure, has occupied surface states/resonances that lie about 1 eV be low the valence-band maximum in excellent agreement with angle-resolve d photoemission data, and forms a (2 x 2) pattern that may explain the low-energy electron-diffraction data. This surface structure has mixe d-bond arrangements of a graphite structure and a diamond structure.