Energetics of positron states trapped at vacancies in solids

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© 2007 American Physical Society (APS). This is the accepted version of the following article: Makkonen, I. & Puska, Martti J. 2007. Energetics of positron states trapped at vacancies in solids. Physical Review B. Volume 76, Issue 5. 054119/1-10. ISSN 1550-235X (electronic). DOI: 10.1103/physrevb.76.054119, which has been published in final form at http://journals.aps.org/prb/abstract/10.1103/PhysRevB.76.054119.
Journal Title
Journal ISSN
Volume Title
School of Science | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2007
Department
Teknillisen fysiikan laitos
Department of Applied Physics
Major/Subject
Mcode
Degree programme
Language
en
Pages
054119/1-10
Series
Physical Review B, Volume 76, Issue 5
Abstract
We report a computational first-principles study of positron trapping at vacancy defects in metals and semiconductors. The main emphasis is on the energetics of the trapping process including the interplay between the positron state and the defect’s ionic structure and on the ensuing annihilation characteristics of the trapped state. For vacancies in covalent semiconductors the ion relaxation is a crucial part of the positron trapping process enabling the localization of the positron state. However, positron trapping does not strongly affect the characteristic features of the electronic structure, e.g., the ionization levels change only moderately. Also, in the case of metal vacancies, the positron-induced ion relaxation has a noticeable effect on the calculated positron lifetime and momentum distribution of annihilating electron-positron pairs.
Description
Keywords
positron states, density functional theory, positron annihilation
Other note
Citation
Makkonen, I. & Puska, Martti J. 2007. Energetics of positron states trapped at vacancies in solids. Physical Review B. Volume 76, Issue 5. 054119/1-10. ISSN 1550-235X (electronic). DOI: 10.1103/physrevb.76.054119.