Subatomic-scale resolution with SPM: Co adatom on p(2 × 1)Cu(110):O

We study the limits of SPM subatomic resolution in imaging orbital magnetic features on a model system of a Co atom on a p(2 × 1)Cu(110):O surface. We show that scanning tunneling spectroscopies allow the determination of the occupation of the Co d shells and the value of the Hubbard U in the DFT + U modeling, and that standard near-contact AFM can in principle image the asymmetry due to partial filling of the d shells at close distances in the small-amplitude regime. Due to the partially ionic character of Co, a faint asymmetry is predicted to also arise in the electrostatic force. We anticipate these features to be even stronger for a transition metal adsorbate featuring larger departures from sphericality in charge/spin densities. (paper)