Reconstruction and Thermal Stability of the Cubic SiC (001) Surfaces

The (001) surfaces of cubic SiC were investigated with ab initio molecular dynamics simulations. We show that C-terminated surfaces can have different $c(2\times 2)$ and $p(2\times 1)$ reconstructions, depending on preparation conditions and thermal treatment, and we suggest experimental probes to identify the various reconstructed geometries. Furthermore, we show that Si-terminated surfaces exhibit a weak $c(2\times 1)$ reconstruction at $T=0\mathrm{}$, whereas above room temperature they oscillate between a dimer row and an ideal geometry below 500 K, and sample several patterns including a $c(4\times 2)$ above 500 K.