Density functional calculations on the intricacies of Moiré patterns on graphite

摘要: Scanning tunneling microscopy (STM) imaging has detected a wealth of puzzling features on the surface highly oriented pyrolytic graphite, among them, anomalously large superperiodicities, called Moire patterns, caused by lattice-mismatched top layer graphite. Exactly, graphene rotates with respect to graphite substrate. Such rotation gives rise different types local stackings in regions. As STM mapping is dependent differences density states at Fermi level, variations brightness differentiate regions stackings. Bright areas (visible areas) correspond AABABAB... stackings, whereas dark (hidden BABABAB... or CABABAB... ones. We have programmed an algorithm which first built systematically whole range structures and afterwards quantified percentages Finally, periodic functional theory calculations been performed selection order draw energy profile between two layers.