[2Fa03-07] SS1

[2Fa04] Thickness-dependence of van Hove singularity in Li-intercalated graphene

*Satoru Ichinokura¹, Masayuki Toyoda¹, Mizuki Hashizume¹, Kentaro Horii¹, Syotaro Kusaka¹, Shin-ichiro Ideta², Kiyohisa Tanaka², Ryota Shimizu³, Taro Hitosugi³, Susumu Saito¹, Toru Hirahara¹ (1. Department of Physics, Tokyo Institute of Technology, 2. UVSOR Facility, Institute for Molecular Science, 3. Department of Applied Chemistry, Tokyo Institute of Technology)

Unconventional superconductivity can be introduced in graphene by fine-tuning the van Hove singularity (VHS) position near the Fermi level. In this study, we examined the binding energy of VHS upon lithium intercalation into graphene with different thicknesses. From bilayer to multilayer, VHS shifted from the vicinity of the Fermi level to the occupied state by 60 meV. We performed first-principle calculations without and with the substrate. The former showed that interlayer interaction moves VHS more than experiments. The latter indicated that hybridization with the surface state of the substrate alters the dispersion of the Dirac bands, which can pin the VHS near the Fermi level.