ULTRA-THIN EPITAXIAL-FILMS OF GRAPHITE AND HEXAGONAL BORON-NITRIDE ONSOLID-SURFACES

In this article, we have reviewed the recent progress of the experimen tal studies on ultra-thin films of graphite and hexagonal boron nitrid e (h-BN) by using angle-resolved electron spectroscopy together with o ther techniques. The fundamental properties of these high-quality film s are discussed on the basis of the data on dispersion relations of va lence electrons, phonon dispersion etc. The interfacial orbital mixing of the pi-state of the monolayer graphite (MG) with the d states of t he reactive substrates is the origin for the phonon softening, expansi on of the nearest-neighbour CC distance, modification of the pi-band, low work function, and two-dimensional plasmons with high electron den sity, etc. In the cases of weak mixing at the interface between the MG and relatively inert substrates, the observed properties of the MG ar e very close to the bulk ones. In contrast to the case for MG, the int erfacial interaction between the h-BN monolayer and the substrate is w eak.