Charge transfers at metal/oxide interfaces: a DFT study of formation of Kδ+and Auδ−species on MgO/Ag(100) ultra-thin films from deposition of neutral atoms
- 9 May 2006
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Physical Chemistry Chemical Physics
- Vol. 8 (28), 3335-3341
- https://doi.org/10.1039/b604288k
Abstract
Ultra-thin oxide films grown on a metal substrate and of thickness smaller than 1 nm may exhibit unusual properties with respect to thicker films or single crystal oxide surfaces. In a previous study [G. Pacchioni, L. Giordano and M. Baistrocchi, Phys. Rev. Lett., 2005, 94, 226104] we have suggested that a Au atom adsorbed on a MgO/Mo(100) thin film becomes negatively charged by direct electron tunneling from the Mo metal and that this is related to the low MgO/Mo(100) work function. Here we show, based on periodic DFT supercell calculations, that charge transfer can occur also in the opposite direction by adsorption of electropositive K atoms on MgO/Ag(100) films. We predict the occurrence of a charge transfer also for Au on MgO/Ag(100) films despite the fact that here the work function is 1 eV larger than in MgO/Mo(100). The formation of a layer of adsorbed negative (Auδ−/MgO/Ag) or positive (Kδ+/MgO/Ag) adsorbates results in an increase or decrease, respectively, of the MgO/Ag(100) work function as predicted by the classical Gurney model for ionic adsorbates on metal surfaces.Keywords
This publication has 46 references indexed in Scilit:
- Electronic properties calculation ofthin films adsorbed on semi-infinitePhysical Review B, 2004
- Identification of defect sites on oxide surfaces by metastable impact electron spectroscopyProgress in Surface Science, 2003
- Paramagnetic Defect Centers at the MgO Surface. An Alternative Model to Oxygen VacanciesJournal of the American Chemical Society, 2002
- A study of the secondary electron yield γ of insulator cathodes for plasma display panelsIEEE Transactions on Electron Devices, 2001
- Mg clusters on MgO surfaces: study of the nucleation mechanism with MIES and ab initio calculationsFaraday Discussions, 1999
- Systematic Density Functional Study of the Adsorption of Transition Metal Atoms on the MgO(001) SurfaceThe Journal of Physical Chemistry B, 1997
- Projector augmented-wave methodPhysical Review B, 1994
- Ab initio effective core potentials for molecular calculations. Potentials for K to Au including the outermost core orbitalsThe Journal of Chemical Physics, 1985
- Special points for Brillouin-zone integrationsPhysical Review B, 1976
- Electronic structure of a metal-semiconductor interfacePhysical Review B, 1976