Structure and spectroscopy of surface defects from scanning force microscopy: Theoretical predictions

A possibility to study surface defects by combining noncontact scanning for ce microscopy (SFM) imaging with atomically resolved optical spectroscopy i s demonstrated by modeling an impurity Cr3+ ion at the MgO(001) surface wit h a SFM rip. Using a combination of the atomistic simulation and the ab ini tio electronic structure calculations, we predict a topographic noncontact SFM image of the defect and show that its optical transitions can be either enhanced or suppressed depending on the tip atomistic structure and its po sition relative to the defect. These effects should allow identification of certain impurity species through competition between radiative and nonradi ative transitions.