Growth and thermal behaviour of NiO nanolayers on Pd(100)

Surface structure of nickel oxide layers on a Rh(111) surface

“…9c, taken from the 2 ML NiO surface, contains a phonon loss peak at 68 meV, which is identified as a Fuchs-Kliewer surface phonon involving ionic displacements normal to the NiO(100) crystal surface [38]. The low-energy shoulder at 54 meV has been also reported in HREELS spectra of NiO films on Ni(100) [39] and Pd(100) [40] surfaces. Interestingly, under a somewhat lower oxygen pressure of 1×10 −7 mbar, the NiO(100) phase transforms into a surface which exhibits a sharp p(2×2) LEED pattern (not shown), corresponding to a lattice constant of about 5 Å.…”

Self-organized chromium oxide monolayers on Fe(001)

“…11 The interest in one-layer-thick oxides is manifold, in particular (i) two-dimensional oxides can be seen as model systems for the oxide/metal interface, allowing investigation by means of high-resolution scanning probe techniques; (ii) the vertical confinement and the elastic and electronic coupling with the metallic substrate allows stabilizing stoichiometries and atomic structures that can differ with respect to the corresponding bulk terminations, with important implications in chemical reactivity, 12,13 adsorption properties, 14 and magnetic ordering 15 of the resulting structures; and (iii) the wetting layer can represent the precursor phase for the growth of thicker films. 16,17 Single layers of transition metal oxides have been stabilized on noble and quasinoble metals such as, for instance, Pd, 18,19 Ag, 20,21 Pt, 22,23 Au, 24 and Ir. 25 In these cases, growth techniques such as reactive deposition (i.e., metal deposition in oxygen atmosphere) and/or postoxidation are typically applied, leading to ordered phases and well-defined oxidemetal interfaces.…”

High Resolution STM Imaging

“…These areas of increased density reveal the two-and fourfold symmetry representative of each tip's crystallographic orientation. However, for the W [111] tip, the areas of increased density do not reveal the threefold symmetry that one would expect [140]. These results suggest that the highest spatial resolution can be achieved in STM experiments using W [111] tips which have symmetrical charge density distribution along the tip axis even at relatively small distances from the surface cluster.…”

“…This result independently proves the feasibility of the orbital resolution STM [22][23][24] and AFM [140] experiments with tungsten tips demanding the tunneling gaps below 2.5 Å . Figure 15.14a-c shows the isosurfaces of the change in the electron density calculated for the [011]-, [111]-, and [001]-oriented tungsten tips interacting with the helium atom located directly below the front atom of the tips [139]. Figure 15.14d-f illustrates that increased density (dark red) is seen between the front atom of the W[011] and W[001] tips and the atoms in the second tip layer to which it is bonded.…”