Van Hove singularity and Lifshitz transition in thickness-controlled Li-intercalated graphene

We demonstrate a method to control the Fermi level around Van Hove singularity (VHS) in Li-intercalated graphene on SiC substrate. By angle-resolved photoemission spectroscopy, we observed clear Lifshitz transition vicinity of VHS when thickness exceeds four layers. calculated band structure multilayer system with different stacking sequences and Li layer. The so-called stage 2 model reproduces transition, where occupies every other interlayer graphene. In addition, found that sizable Schottky barrier is formed between These properties allow us explore electronic phase diagram by controlling thickness.