ABSTRACT
The Al-related graphene systems are one of the widely studied materials. The high sensitivity of Al atoms is quite suitable for energy and environment engineering. The rich physical and chemical phenomena are closely related to various orbital interactions. The multi-orbital hybridizations between Al adatoms and graphene deserve a thorough investigation. Adatom arrangements are optimized through the detailed analyses on the ground-state energies, bismuth binding energies, and Bi-Bi interaction energies of different heights, inter-adatom distances, adsorption sites, and hexagonal positions. The optimal Al adsorption position is the hollow site, regardless of concentration and distribution. The carbon-dominated energy bands are dramatically shifted by the Al-adatom absorption. The Dirac-cone structure is almost preserved in the Al-absorbed graphene. The multi-orbital hybridizations of Al-adsorbed graphenes are directly revealed in the spatial charge distributions. The multi-orbital hybridizations in C-C, Al-C, and Al-Al bonds can diversify the special structures in density of states (DOS).
