Reemitted positron spectroscopy of near-surface defects

Journal Article · Wed Aug 01 04:00:00 EDT 1990 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.42.1910· OSTI ID:6390316

McMullen, T ^[1]; Stott, M J ^[2]

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1. Physics Department, Virginia Commonwealth University, Richmond, VA (USA)
2. Department of Physics, Queen's University, Kingston, Ontario (Canada)

Simulations of the energy spectra of positrons reemitted from aluminum that contains subsurface defects are presented. The defects are vacancies and divacancies that have positron trapping rates which depend strongly on energy in the {approximately}1-eV energy range due to low-lying positron {ital p}-wave scattering resonances. Because of this, the energy spectra are depleted in the eV energy range when the defects are present. There is also depletion in this energy range with increasing sample temperature because the increased positron-phonon scattering at the higher temperatures impedes the motion of the positrons back to the surface. The simulations use a diffusion model of the positron energy-loss and scattering processes. The results are compared with the experimental data of Nielsen, Lynn, and Chen (Phys. Rev. Lett. 57, 1789 (1986)).

• DOE Contract Number: FG05-87ER45316
• OSTI ID: 6390316
• Journal Information: Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 42:4; ISSN PRBMD; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
ALUMINIUM
ANTILEPTONS
ANTIMATTER
ANTIPARTICLES
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DIFFUSION
ELEMENTARY PARTICLES
ELEMENTS
ENERGY LOSSES
ENERGY SPECTRA
FERMIONS
LEPTONS
LOSSES
METALS
POINT DEFECTS
POSITRONS
SCATTERING
SIMULATION
SPECTRA
SURFACES
VACANCIES