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Comparative theoretical study of the Ag-MgO (100) and (110) interfaces

Zhukovskii, YF; Kotomin, EA; Jacobs, PWM; Stoneham, AM; Harding, JH; (1999) Comparative theoretical study of the Ag-MgO (100) and (110) interfaces. Surf Science , 441 (2/3) 373 - 383. 10.1016/S0039-6028(99)00847-X. Green open access

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Abstract

We have calculated the atomic and electronic structures of Ag-MgO(100) and (110) interfaces using a periodic (slab) model and an ab initio Hartree-Fock approach with a posteriori electron correlation corrections. The electronic structure information includes interatomic bond populations, effective charges, and multipole moments of ions. This information is analyzed in conjunction with the interface binding energy and the equilibrium distances for both interfaces for various coverages. There are significant differences between partly covered surfaces and surfaces with several layers of metal, and these can be understood in terms of electrostatics and the electron density changes.For complete monolayer (1:1) coverage of the perfect MgO(100) surface, the most favorable adsorption site energetically for the Ag atom is above the surface oxygen. However, for partial (1:4) coverage of the same surface, the binding energies are very close for all the three likely adsorption positions (Ag over O, Ag over Mg, Ag over a gap position),For a complete (1:1) Ag monolayer coverage of the perfect MgO(110) interface, the preferable Ag adsorption site is over the interatomic gap position, whereas for an Ag bilayer coverage the preferred Ag site is above the subsurface Mg2+ ion (the bridge site between two nearest surface O2- ions). In the case of 1:2 layer coverage, both sites are energetically equivalent. These two adhesion energies for the (110) substrate are by a factor of two to three larger than over other possible adsorption sites on perfect(110) or (100) surfaces.We compare our atomistic calculations for one to three Ag planes with those obtained by the shell model for 10 Ag planes and the Image Interaction Model addressing the case of thick metal layers. Qualitatively, our ab initio results agree well with many features of these models. The main charge redistributions are well in line with those expected from the Image Model. There is also broad agreement in regard to orders of magnitude of energies. (C) 1999 Elsevier Science B.V. All rights reserved.

Type: Article
Title: Comparative theoretical study of the Ag-MgO (100) and (110) interfaces
Open access status: An open access version is available from UCL Discovery
DOI: 10.1016/S0039-6028(99)00847-X
Publisher version: http://dx.doi.org/10.1016/S0039-6028(99)00847-X
Language: English
Additional information: Text made available to UCL Discovery by kind permission of Elsevier B.V., 2012
Keywords: (100) and (110) interfaces, adhesion, adsorption, Ag-MgO, Hartree-Fock method, image interaction model, METAL-OXIDE INTERFACES, ABINITIO HARTREE-FOCK, AG/MGO(001) INTERFACE, ELECTRONIC-STRUCTURE, CERAMIC INTERFACES, IMAGE INTERACTIONS, MGO(001) SURFACE, MGO(100) SURFACE, ADSORPTION, ADHESION
UCL classification: UCL > Provost and Vice Provost Offices
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > London Centre for Nanotechnology
URI: http://discovery.ucl.ac.uk/id/eprint/53154
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