Modeling the $c(4\mathrm{}\times 2)$ reconstruction of $\beta -\mathrm{SiC}\mathrm{}\left(001\right)\mathrm{}$

We perform ab initio plane-wave supercell geometry local-density approximation calculations on two candidate models of the $c(4\mathrm{}\times 2)$ reconstruction of the $\beta -\mathrm{SiC}\mathrm{}\left(001\right)\mathrm{}$ surface: the alternating up down dimer model, and the missing row asymmetric dimer (MRAD) model. Our results support the contention of Lu et al. [W. Lu, P. Krüger, and J. Pollmann, Phys. Rev. Lett. 81, 2292 (1998)], that the MRAD model is favored for all allowed values of chemical potential, and suggest a reinterpretation of previous experiments.