ENERGETICS OF THE ALPHA-SIC(0001)-(3X3) SURFACE RECONSTRUCTION

The paper presents an analysis of the energetics of a few possible can didates for the structural model of the (3 x 3) reconstruction of the alpha-SiC(0001) surface. The analysis is based on quantum chemical cal culations of the MNDO type (AMI parametrization). The results indicate that of the models tested, the newly proposed model of Starke et al. [Phys. Rev. Lett. 80 (1998) 758] is the only energetically feasible mo del for the reconstruction. Moreover, Si atoms in this and other struc tures of lower Si coverage appear to be bonded to the stoichiometric s urface more strongly than single Si adatoms in the (root 3 x root 3) p attern. The last result confirms the experimental finding of Tsukamoto et al. [T. Tsukamoto, M. Hirai, M. Kusaka, M. Iwami, T. Ozawa, T. Nag amura, T. Nakata, Surf. Sci. 371 (1997) 316] that Si adatoms are not l ikely candidates for the structural elements building the (root 3 x ro ot 3) reconstruction. (C) 1998 Elsevier Science B.V. All rights reserv ed.