IMAGING INSULATING OXIDES BY ELEVATED-TEMPERATURE STM

By using elevated-temperature scanning tunnelling microscopy (STM) we have imaged the UO2(111), UO2(110), and NiO(001) surfaces, and have ob tained atomic resolution data that are comparable in quality with imag es of other oxides that can be imaged at room temperature. Electronic structure modelling is used to interpret the STM images. On the UO2(11 1) surface we image the U sites in empty states, and it is also possib le to observe interstitial oxygen on this surface that packs into a (r oot 3 x root 3) R 30 degrees oxygen overlayer. The UO2(110) surface ha s been imaged at atomic resolution and displays a row structure commen surate with the (1 x 1) bulk termination. On NiO(001), Ni and O sites are imaged in empty and filled states, respectively, which is demonstr ated by comparing the lattices around characteristic defect sites.