Low-energy electron and positron diffraction measurements and analysis on Cu(100)

Journal Article · Sun Mar 01 04:00:00 EST 1987 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.35.3102· OSTI ID:7156524

Mayer, R; Zhang, C; Lynn, K G; Frieze, W E; Jona, F; Marcus, P M

The results of an experimental study and quantitative analysis of the intensity versus energy (I-V) curves are reported for low-energy electron diffraction and low-energy positron diffraction (LEPD) with a brightness-enhanced electrostatically focused positron beam. In a close comparative study, the incident electrons and positrons scattered at a large incident polar angle (thetagreater than or equal to50/sup 0/) with respect to the surface normal off clean Cu(100) and the I-V spectra from six and seven diffraction beams were taken with electrons and positrons, respectively. The analysis of the experimental data from the electron studies indicates first- and second-layer relaxation that is consistent with earlier results. Use of the structure derived from the electron studies, analysis of the I-V curves from the LEPD studies suggests that the attenuation for positrons is greater than the value for electrons over the energy range 50--400 eV, possibly as a result of the enhanced electron-image cloud surrounding the positron. The real part of the inner potential is 0 eV for positrons compared with 11 eV for electrons, in rough agreement with predictions. Further, the best agreement between experiment and calculation for LEPD I-V curve analysis tends to favor the potential formed by changing of the sign of the Coulomb term (relative to electrons), eliminating the exchange, and retaining the correlation term.

• Research Organization: Department of Physics, Brookhaven National Laboratory, Upton, New York 11973
• DOE Contract Number: AC02-76CH00016
• OSTI ID: 7156524
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 35:7; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
656003 -- Condensed Matter Physics-- Interactions between Beams & Condensed Matter-- (1987-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ATTENUATION
COHERENT SCATTERING
COLLISIONS
COPPER
CRYSTAL FACES
CRYSTAL STRUCTURE
DIFFRACTION
ELECTRON DIFFRACTION
ELEMENTS
EXCHANGE INTERACTIONS
INTERACTIONS
MEASURING METHODS
METALS
POSITRON COLLISIONS
SCATTERING
TRANSITION ELEMENTS