ATOMIC-STRUCTURE OF BETA-SIC(100) SURFACES - A STUDY USING THE TERSOFF POTENTIAL

Atomic structure of the beta-SiC(100) surface is examined in a theoretical study using the empirical Tersoff potential. The surface energy is evaluated using several models of the atomic structure for three different surface compositions. The previously proposed Si dimer row structure of the (2 x 1) surface is supported by our calculations. For the (3 x 2) surface with excess silicon, we propose a new model, an alternate dimer row model, which we find to be energetically favored over the added dimer row model of Hara et al. [Surf. Sci. 231 (1990) L196]. Our calculations on the C-terminated c(2 x 2) surface favor the staggered dimer model of Bermudez and Kaplan [Phys. Rev. B 44 (1991) 11149] over the model of Powers et al. [Phys. Rev. B 44 (1991) 11159] placing C-dimers at Si bridge sites. However, the large charge transfer observed in tight-binding calculations of the latter model makes the empirical Tersoff potential less reliable for this surface.