▎ 摘　　要

We study within a van der Waals density functional theory framework the structural and electronic properties of Ge-intercalated epitaxial graphene on SiC(0001). We argue that the insertion of Ge adatoms at the graphene/SiC interface results in an almost complete detachment of the graphitic layer from the substrate. A stable electron-doped phase is obtained as a result of the pinning of the Fermi level by sp(3)-type Ge dangling-bond states. Stability is preserved when germanium atoms substitute Si/C atoms of the SiC substrate, while it is compromised when Ge is additionally chemisorbed on the graphene surface. Results are in good agreement with recent experiments. (C) 2011 The Japan Society of Applied Physics