Bulk and surface electronic structure of NiO and CoO: a comparative ab initio LSDA + U analysis and application to the interpretation of STM images

摘要

Atomically resolved scanning tunneling microscope images of (0 0 1) cobalt and nickel monoxide surfaces are interpreted on the basis of LSDA + U surface electronic structure calculations. Different symmetry of dangling unoccupied d-bonds on CoO(0 0 1) and NiO(0 0 1) explains the origin of an order of magnitude difference in the contrast of tunnelling images observed for the two surfaces.