  To achieve atomic-level characterization of the diamond (001) surface,
persistent efforts have been made over the past few decades. The motivation
behind the pursuit extends beyond investigating surface defects and adsorbates;
it also involves unraveling the mystery of the smooth growth of diamond.
However, the inherently low conductivity and the short C-C bonds render atomic
resolution imaging exceptionally challenging. Here, we successfully overcame
these challenges by employing non-contact atomic force microscopy with reactive
Si tips. Atomic resolution imaging was achieved even at room temperature. With
density-functional-theory calculations, we clarified that the critical factors
for atomic resolution are in the formation of tilted C-Si bonds between
scanning probes and surfaces, along with reordering of the surface C-C dimers.
Implications of the findings extend beyond the realm of surface
characterization. The present atomic-resolution microscopies drive future
advancements in diamond technologies by providing avenues for identifying
dopants and constructing artificial nanostructures.
