X-ray photoelectron diffraction of NiO: Experiments and calculations in an extended single-scattering-cluster model

1993 ◽  
Vol 48 (10) ◽  
pp. 6919-6926 ◽  
Author(s):  
C. Scharfschwerdt ◽  
T. Liedtke ◽  
M. Neumann ◽  
T. Straub ◽  
P. Steiner
Keyword(s):  
Cluster Model ◽  
Single Scattering ◽  
X Ray ◽  
Photoelectron Diffraction

STRUCTURAL DETERMINATION OF THE Si/Cu(110) INTERFACE BY PHOTOELECTRON DIFFRACTION

1997 ◽  
Vol 04 (06) ◽  
pp. 1331-1335 ◽  
Author(s):  
C. ROJAS ◽  
J. A. MARTÍn-GAGO ◽  
E. ROMÁN ◽  
G. PAOLUCCI ◽  
B. BRENA ◽  
...  
Keyword(s):  
Room Temperature ◽  
Structural Parameters ◽  
Single Scattering ◽  
Structural Determination ◽  
X Ray ◽  
Photoelectron Diffraction ◽  
First Order ◽  
Proposed Model ◽  
Laboratory Source

Deposition of 0.5 Si monolayer (ML) on a Cu (110) surface at room temperature (RT) leads to the formation of a c(2×2) LEED pattern. In order to find out the surface atomic structure of this ordered phase, X-ray photoelectron diffraction (XPD) azimuthal scans at different photon energies and full hemispherical XPD patterns of the Si 2 p core level have been measured using both synchrotron radiation and a laboratory source. We present an atomic model for the surface structure based on the examination of forward scattering and first order interference XPD features. Refinement of the structural parameters was achieved by performing single scattering cluster (SSC) calculations. In the proposed model Si atoms replace Cu atoms at the surface along the [Formula: see text] atomic rows.

THE SURFACE STRUCTURE OF A LOW Pd Cu/Pd-(110) CRYSTAL ALLOY

1994 ◽  
Vol 01 (04) ◽  
pp. 569-571 ◽  
Author(s):  
M. BOWKER ◽  
M. NEWTON ◽  
S.M. FRANCIS ◽  
M. GLEESON ◽  
C. BARNES
Keyword(s):  
Surface Structure ◽  
Surface Region ◽  
Single Scattering ◽  
Alloy Surface ◽  
High Concentration ◽  
Near Surface ◽  
X Ray ◽  
Photoelectron Diffraction ◽  
Layer 2

X-ray photoelectron diffraction studies of this alloy surface have been carried out and indicate that there is a significant expansion of the lattice in the near-surface region due to the high concentration of Pd in layer 2. Preliminary single scattering calculations lend support to this proposal for the surface structure, and place this expansion in the subsurface mainly between layers 2 and 3.

X-Ray Photoelectron Diffraction Measurements of Hexagonal GaN(0004) Thin Films

1997 ◽  
Vol 468 ◽  
Author(s):  
R. Denecke ◽  
J. Morais ◽  
C. Wetzel ◽  
J. Liesegang ◽  
E. E. Haller ◽  
...  
Keyword(s):  
Thin Films ◽  
Theoretical Calculation ◽  
Intensity Ratio ◽  
Single Scattering ◽  
Forward Scattering ◽  
Surface Contamination ◽  
Cluster Calculation ◽  
X Ray ◽  
Photoelectron Diffraction ◽  
Sapphire Substrates

ABSTRACTWe report on the first scanned-angle x-ray photoelectron diffraction measurements on GaN(0001) in the wurtzite structure, as grown on sapphire substrates using MOCVD. These as-grown samples reveal forward scattering peaks in agreement with a theoretical calculation using a single scattering cluster calculation. The surface contamination by O and C does not exhibit any clear structure. From the combination of experiment and theoretical calculation and from a simple intensity ratio argument the surface termination for these samples could be determined to be N. The data also indicate that C is on average closer to the GaN surface than O.

GROWTH OF ULTRATHIN Mn FILMS ON Ag(100)

1997 ◽  
Vol 04 (06) ◽  
pp. 1251-1256 ◽  
Author(s):  
P. SCHIEFFER ◽  
M. C. HANF ◽  
C. KREMBEL ◽  
M. H. TUILIER ◽  
G. GEWINNER ◽  
...  
Keyword(s):  
Polar Angle ◽  
Atomic Plane ◽  
Atomic Layer ◽  
Single Scattering ◽  
X Ray ◽  
Photoelectron Diffraction ◽  
Maximum Value ◽  
Fcc Lattice ◽  
Place Exchange ◽  
X Ray Absorption

Mn films with a thickness of one monolayer have been deposited, in ultrahigh vacuum, on a Ag (100) single crystal at room temperature, and analyzed by X-ray photoelectron diffraction (XPD) and surface extended X-ray absorption fine structure (SEXAFS). The strong enhancement of the X-ray photoelectron Mn2p3/2 signal along the Ag[1100] direction indicates that a substantial fraction of the Mn atoms is located within the second topmost atomic layer. The SEXAFS data demonstrate that the Mn – Ag and Mn – Mn first neighbor distances are the same as the Ag – Ag distances in the Ag lattice; as a result, the atoms occupy Ag sites on the fcc lattice. Comparison of the experimental data with FEFF calculations indicates that a superficial Mn – Ag alloy is formed. If the film is mildly (330 K) annealed, the contrast in the XPD Mn 2p 3/2 modulations versus polar angle increases and reaches a maximum value of 60%. As confirmed by single scattering simulations, these results mean that atomic place exchange occurs between Mn and Ag atoms, and eventually the second atomic plane of the sample is constituted mainly by Mn atoms, whereas the first atomic layer is a pure Ag plane, i.e. a buried atomic Mn monolayer is formed.

Angle-Resolved X-Ray Photoelectron Spectroscopy for the Characterization of GaAs(001) and Inp(001) Surfaces

1987 ◽  
Vol 94 ◽  
Author(s):  
Patrick Alnot ◽  
J. Olivier ◽  
F. Wyczisk
Keyword(s):  
Kinetic Energy ◽  
Electron Scattering ◽  
Photoelectron Spectroscopy ◽  
Cluster Model ◽  
Spherical Wave ◽  
Single Scattering ◽  
Photoemission Spectroscopy ◽  
X Ray ◽  
Quantitative Measurements

ABSTRACTElectron scattering and diffraction in X-ray photoemission spectroscopy (XPS) have been used to characterize GaAs(001) and InP(001) chemically etched surfaces. 6a(3d),As(3d), In(4d) and P(2p) photoelectrons have been observed as a function of polar angles for the two [1–10] and [110] azimuths For kinetic energy range of these photoelectrons the experimental results have been correctly predicted by the single-scattering cluster model with spherical-wave corrections.The problems of quantitative measurements in XPS have been discussed in relation with the diffraction phenomena.

The Overlayer Structure on the Si(001)-(2×3)-Ag Surface Determined by X-ray Photoelectron Diffraction

1998 ◽  
Vol 05 (05) ◽  
pp. 953-958 ◽  
Author(s):  
M. Shimomura ◽  
T. Abukawa ◽  
M. Higa ◽  
M. Nakamura ◽  
S. M. Shivaprasad ◽  
...  
Keyword(s):  
Multiple Scattering ◽  
Single Scattering ◽  
Unit Cell ◽  
Single Domain ◽  
X Ray ◽  
Photoelectron Diffraction ◽  
Other Information

X-ray photoelectron diffraction (XPD) patterns of Ag 3d electrons from a single domain Si(001)-(2×3)-Ag surface were examined. Single scattering cluster and multiple scattering cluster simulations of the Ag 3d XPD patterns indicate an overlayer that contains four Ag atoms aligned almost linearly along the threefold direction in the unit cell on the Si(001) surface. The four-Ag-atom arrangement is discussed in the light of other information obtained by STM, LEEM and photoemission studies, finding it very feasible.

DYNAMICAL ANALYSIS OF X-RAY PHOTOELECTRON DIFFRACTION FROM W(001)c(2×2)-Ag AND -Au SURFACES

1995 ◽  
Vol 02 (06) ◽  
pp. 795-804 ◽  
Author(s):  
X. CHEN ◽  
T. ABUKAWA ◽  
J. TANI ◽  
S. KONO
Keyword(s):  
Multiple Scattering ◽  
Single Scattering ◽  
Dynamical Analysis ◽  
Dynamical Study ◽  
X Ray ◽  
Photoelectron Diffraction ◽  
Local Structures ◽  
Multiple Scattering Effect ◽  
High Kinetic Energy ◽  
Past Conditions

The local structures of W (001) c (2×2)- Ag and - Au [refer to as c (2×2)- Ag and - Au ] surfaces have been studied by x-ray photoelectron diffraction (XPD) for Ag-3d and Au-4f emissions with both multiple-scattering and single-scattering cluster approaches. Our dynamical study has revealed that the outermost layers of these surfaces form rumpled alloy structures, and the height of adsorbate atoms is 0.3±0.1 Å above that of W atoms in the top layer, and both adsorbate and tungsten atoms are at fourfold symmetric sites on the surfaces. It is also found in this study that there is a strong multiple-scattering effect on these surfaces, and a kinematical analysis fails completely on XPD from the c (2×2)- Ag surface at a high kinetic energy of 1115 eV, where the validity of the single-scattering theory was taken for granted in the past. Conditions that may result in such a strong multiple scattering in the systems are discussed in this paper.

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