The Pd (100)-(root 5 x root 5)R27 degrees-O surface oxide: A LEED, DFT and STM study

• Using low energy electron diffraction (LEED), density functional theory (DFT) and scanning tunneling microscopy (STM), we have re-analyzed the Pd(100)-(root 5 x root 5)R27 degrees-O surface oxide structure consisting, in the most recent model, of a strained PdO(101) layer on top of the Pd(100) surface [M. Todorova et al., Surf. Sci. 541 (2003) 101]. Both, DFT simulations using the Vienna Ab initio Simulation Package (VASP) and tensor LEED I(P) analysis of newly acquired LEED experimental data, show that the PdO(101) model is essentially correct. However, compared to the previous study, there is a horizontal shift of the PdO(101) layer with respect to the Pd(100) substrate. The atomic coordinates derived by DFT and LEED (R-P = 0.162) are in excellent agreement with each other. We also present STM images with atomic resolution showing domain boundaries on the surface oxide and discuss the bonding geometry between the surface oxide and the substrate. (c) 2007 Elsevier B.V. All rights reserved.

Ämnesord

NATURVETENSKAP  -- Fysik -- Atom- och molekylfysik och optik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Atom and Molecular Physics and Optics (hsv//eng)

Nyckelord

scanning tunneling microscopy

functional calculations

density

low energy electron diffraction (LEED)

palladium

oxidation

low index

single crystal surfaces

surface structure

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