Jj. Dong et Da. Drabold, RING FORMATION AND THE STRUCTURAL AND ELECTRONIC-PROPERTIES OF TETRAHEDRAL AMORPHOUS-CARBON SURFACES, Physical review. B, Condensed matter, 57(24), 1998, pp. 15591-15598
In this paper, we report first-principles structural models of surface
s of tetrahedral amorphous carbon (ta-C). The topology and defect stru
cture of the amorphous surfaces are analyzed at the atomistic level. W
e examine the transition of the local bonding environment from the bul
k to the surface. Comparing the surface with the bulk, many more surfa
ce atoms are threefold coordinated and planar rings or chains are form
ed with the sp(2) bonds. This ''graphization'' character of the ta-C s
urface also significantly influences its electronic properties. Electr
ons are easily delocalized within these surface sp(2) rings/chains and
some of the surface electronic eigenstates become extended along the
surface through such rings/chains. The implications of surface graphiz
ation for the growth and surface conduction are briefly discussed.