Theory of angle-resolved photoemission extended fine structure

Journal Article · Tue Jul 15 04:00:00 EDT 1986 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.34.778· OSTI ID:5661129

Barton, J J; Robey, S W; Shirley, D A

We present a theory for photoelectron scattering in the 100--1000 eV energy range designed to simulate experimental measurements of angle-resolved photoemission extended fine structure (ARPEFS) from ordered surfaces. The zero-order problem of photoabsorption in the solid is treated first, followed by a scattering problem which incorporates the scattering ion cores in a perturbation series (cluster expansion). The dynamics of core-hole relaxation are discussed, but the dynamical effects are shown to be small. The Taylor-series magnetic-quantum-number expansion is used for the curved-wave, multiple-scattering equations. We argue that a velocity-dependent surface barrier gives primarily an inner potential shift, with no clear evidence for surface electron refraction. Analytic formulas for aperture integration are derived and thermal averaging in a correlated Debye model is extended to multiple scattering. Reasonable values for nonstructural parameters in the theory are shown to give very good simulations of the experimental ARPEFS measurements from c-italic(2 x 2)S/Ni(001) in contrast to previous theoretical calculations. We find, in agreement with full multiple-scattering calculations, that forward focusing is a fundamental feature of ARPEFS and that curved-wave corrections are essential for quantitative results. Since the scattering path-length difference is not appreciably altered by forward scattering, the ARPEFS oscillation frequency is equal to the geometrical path-length difference plus a small potential phase shift, but the amplitude and constant phase of the oscillations cannot be predicted by theories based upon single-scattering or plane-wave approximations.

• Research Organization: Materials and Molecular Research Division, Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720 and Department of Chemistry and Department of Physics, University of California, Berkeley, California 94720
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 5661129
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 34:2; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
CRYSTAL FACES
CRYSTALS
ELECTRON SPECTROSCOPY
ELECTRONS
ELEMENTARY PARTICLES
ELEMENTS
ENERGY RANGE
ENERGY SPECTRA
EV RANGE
EV RANGE 100-1000
FERMIONS
FINE STRUCTURE
LEPTONS
METALS
MULTIPLE SCATTERING
NICKEL
PHOTOELECTRON SPECTROSCOPY
RESOLUTION
SCATTERING
SIMULATION
SMALL ANGLE SCATTERING
SPATIAL RESOLUTION
SPECTRA
SPECTROSCOPY
SURFACES
TRANSITION ELEMENTS