▎ 摘　　要

The heteroatom doping of graphene is a useful method to amplify the outstanding properties of graphene. However, it is difficult to control the disposition of the dopants. By means of first-principles calculations, we show that the substrate-induced doping of epitaxial graphene leads to the formation of silicon doped graphene with a precise location of the dopants in the valley regions between crests. According to our results, in the valleys silicon dopants greatly prefer to replace the carbon atoms of the buffer layer which are bonded to the substrate by a large amount of energy. This selective doping suggests that a siligraphene layer in the g-SiC3 form would be an excellent model for a buffer layer grown on nanometer-sized areas of SiC, thus paving the way to the synthesis of a new two-dimensional material. We predict a stable antiferromagnetical (AF) ordering that behaves electronically as a semiconductor, degenerated with the highest ferromagnetic configuration of the system. A net magnetic moment of 0.65 mu(B) per Si dangling bond was found for both the AF and the most stable ferromagnetic state of the SiC-siligraphene system. Finally, we demonstrate that quasi-free-standing epitaxial siligraphene layers on 6H-SiC(0001) could be obtained by the intercalation of argon atoms. We expect that this work can motivate new experimental studies pursuing the synthesis of SiC3 siligraphene.