Our paper "Forces and Currents in Carbon Nanostructures: Are we imaging atoms?" about atomic resolution of C-based materials has been published in Phys. Rev. Lett. link.aps.org/doi/10.1103/PhysRevLett.106.176101 . The paper has been chosen as Editor Suggestion's and it has been positively reviewd by E.I. Altman in Viewpoint article "Proper carbon ID required" in Physics  physics.aps.org/articles/v4/34.

The unique mechanical and electronic properties of fullerenes, nanotubes, graphene and carbon nanoribbons make them very promising materials for nanotechnological applications. In this paper, we provide a deeper understanding of the atomic-scale contrast observed on these materials with Scanning Probe Microscopes (SPMs): The Scanning Tunneling Microscope (STM) and the Atomic Force Microscope (AFM). The simple honeycomb structure shared by these materials represents both a perfect testing ground and a fundamental challenge for scanning microscopy imaging. Graphite can be imaged with atomic resolution with SPMs even in ambient conditions but, after 25 years of research, still there is no consensus whether the maxima in the atomic scale images correspond to atoms or to the hollow sites. To tackle this long-standing problem, we performed complex first-principles calculations of forces and currents between a tip and carbon nanostructures. Our results explain the rich variety of image patterns observed in both Atomic Force Microscopy and Scanning Tunneling Microscopy experiments in terms of two factors: (i) the tip-sample distance and (ii) the chemical reactivity of the tip. Furthermore, we demonstrate that short-range chemical forces, and not van der Waals interactions, are responsible for the atomic-scale contrast, contradicting the usual interpretation of AFM experiments on carbon nanostructures.

References:

Martin Ondráček, Pablo Pou, Vít Rozsíval, Cesar González, Pavel Jelínek and Rubén Pérez, „Forces and currents in carbon nanostructures: Are we imaging atoms?“ Physical Review Letters 106, 176101 (2011).