Recent scanning tunneling microscopy (STM) experiments display images with star and ellipsoidal like features resulting from unique geometrical arrangements of a few adsorbed hydrogen atoms on graphite. Based on first-principles STM simulations, we have found that the model with three hydrogen atoms, in which the hydrogen atoms are symmetrically placed on the graphene sheet in an equilateral triangle, encompassing a complete hexagon ring of carbon atoms, reproduces the experimentally observed starlike STM patterns. Additionally, we confirm that an ortho-hydrogen pair is the configuration corresponding to the ellipsoidal images. These calculations reveal that when the hydrogen pairs are in the same orientation, they are energetically more stable.
ASJC Scopus subject areas
- Materials Science(all)