Steering the Growth of Metal Ad‐particles via Interface Interactions Between a MgO Thin Film and a Mo Support

Abstract

The coincidence lattice formed between a crystalline MgO film and a Mo(001) support is found to be an ideal template to produce long-range ordered ensembles of Fe and Cr particles for electronic, magnetic and chemical applications. The structural and electronic properties of this super-lattice are analyzed by means of scanning tunnelling microscopy and density functional theory. The different registers of atoms at the interface induce periodic changes in the MgO lattice parameter, in the metal-oxide binding length, and the workfunction. These variations modulate the adsorption landscape for Cr and Fe atoms and give rise to the observed ordering phenomena. Preferred nucleation and growth is revealed in those regions of the coincidence lattice that have a small lattice mismatch with the ad-particles and enable electron-transfer processes with the support

Atomic Scale Characterization of Defects on Oxide Surfaces

“…As expected, the O-Mo configuration features a much smaller binding distance (2.3 Å) than the Mg-Mo registry (3.5 Å), as the O-Mo coupling is highly attractive while a weak repulsion governs the Mg-Mo interaction [183]. As a result, the MgO film is subject to a considerable rumpling, in which the Mg-Mo and O-Mo domains lie on different height levels but are intrinsically flat, while the intermediate regions show a considerable titling.…”

“…The image quality in the latter example is already deteriorated due to the vanishing conductivity of the sample On the atomic scale, the dislocation network is associated to periodic changes in the interface registry that switches from O ions bound on top of Mo atoms to Mg ions sitting on Mo top sites. From the two configurations, the O-Mo registry is energetically preferred [183]. This becomes evident at sub-monolayer coverage, where only square MgO islands with O-Mo registry can be found in the STM images, while the regions of potential Mg-Mo registry are left open (Fig.…”

“…The different interfacial geometries are also reflected in spatial modulation of the adsorption behavior of MgO thin films [183]. In fact, the MgO/Mo coincidence lattice can be used as template to produce well-ordered ensembles of metal particles, as demonstrated for Fe and Cr (Fig.…”

Self-organized nano-structuring of CoO islands on Fe(001)

“…Such a strategy has already been successful in many cases where, in particular, either metallic or semiconducting ordered nano-structure assemblies have been obtained by growing the relative materials on interfaces containing dislocation networks [3][4][5][6]. In other cases, the growth of nanostructures has been realized on oxide substrates similarly characterized by a peculiar distribution of defects [7][8][9]. Much scarcer appears to be the record of cases in which the nanostructured systems consist of the oxide materials themselves [10,11].…”

Morphological and Interfacial Studies of Fe Clusters on SrTiO₃(001) Surfaces

“…Selfassembling of metal clusters on oxide substrates is an effective and simple technique to fabricate these structures, and many approaches are being investigated to achieve a narrow size distribution and an ordered spatial arrangement. These include controlling the compositions, structures and reconstructions, flatness and patterning, polarity of oxide surfaces [6][7][8][9][10]. And in either way, structure and properties of the interface are the utmost important to those systems.…”