▎ 摘　　要

A low-temperature scanning tunnelling microscope (STM) has been used to study the graphene-SiC(0001) interface before and after Li intercalation. For clean graphene, spectroscopy of the differential conductance corroborates previous theoretical findings for the interfacial electronic structure (M. Kajihara et al., Surf. Sci. 647, 39 (2016)). An unambiguous relation between the spectroscopic onset of the interface states with changes in STM images is presented. Li intercalation leads to the disappearance of the 6 x 6 superstructure of clean graphene on SiC(0001) and efficiently suppresses the interface states. The additional doping of graphene due to the presence of Li is reflected by the shift of the Dirac point further below the Fermi energy.