Insights into the epitaxial growth of graphene on SiC substrate: A computational study

Experimentally, the epitaxial growth of graphene on SiC substrate has been observed for both the Si-terminated $(0001)$ or C-terminated $(000\bar {1})$surface of 4H-SiC or 6H-SiC wafers, respectively at sufficiently high temperatures in ultrahigh vacuum [Surface Science \textbf{600}, 3906 (2006); PRB \textbf{77}, 155303 (2008)]. However, the mechanism of the sublimation of Si atoms and the graphitization of excess C atoms on the surface of 4H-SiC or 6H-SiC wafers that leads to the epitaxial growth of graphene on SiC is still unclear. The purpose of this work is to conduct a temperature-dependent study of the evolution of 4H-SiC surfaces using the molecular dynamics scheme based on the SCED-LCAO Hamiltonian [PRB \textbf{74}, 155408 (2006)] so that the evolution of the surface reconstruction of 4H-SiC including the formation of the interface between the substrate and graphene layers can be understood at the microscopic level.