Modeling the momentum distributions of annihilating electron-positron pairs in solids

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dc.contributor Aalto-yliopisto fi
dc.contributor Aalto University en
dc.contributor.author Makkonen, I.
dc.contributor.author Hakala, M.
dc.contributor.author Puska, Martti J.
dc.date.accessioned 2015-09-17T09:01:58Z
dc.date.available 2015-09-17T09:01:58Z
dc.date.issued 2006
dc.identifier.citation Makkonen, I. & Hakala, M. & Puska, Martti J. 2006. Modeling the momentum distributions of annihilating electron-positron pairs in solids. Physical Review B. Volume 73, Issue 3. 035103/1-12. ISSN 1550-235X (electronic). DOI: 10.1103/physrevb.73.035103. en
dc.identifier.issn 1550-235X (electronic)
dc.identifier.uri https://aaltodoc.aalto.fi/handle/123456789/17685
dc.description.abstract Measuring the Doppler broadening of the positron annihilation radiation or the angular correlation between the two annihilation gamma quanta reflects the momentum distribution of electrons seen by positrons in the material. Vacancy-type defects in solids localize positrons and the measured spectra are sensitive to the detailed chemical and geometric environments of the defects. However, the measured information is indirect and when using it in defect identification comparisons with theoretically predicted spectra is indispensable. In this article we present a computational scheme for calculating momentum distributions of electron-positron pairs annihilating in solids. Valence electron states and their interaction with ion cores are described using the all-electron projector augmented-wave method, and atomic orbitals are used to describe the core states. We apply our numerical scheme to selected systems and compare three different enhancement (electron-positron correlation) schemes previously used in the calculation of momentum distributions of annihilating electron-positron pairs within the density-functional theory. We show that the use of a state-dependent enhancement scheme leads to better results than a position-dependent enhancement factor in the case of ratios of Doppler spectra between different systems. Further, we demonstrate the applicability of our scheme for studying vacancy-type defects in metals and semiconductors. Especially we study the effect of forces due to a positron localized at a vacancy-type defect on the ionic relaxations. en
dc.format.extent 035103/1-12
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher American Physical Society (APS) en
dc.relation.ispartofseries Physical Review B en
dc.relation.ispartofseries Volume 73, Issue 3
dc.rights © 2006 American Physical Society (APS). This is the accepted version of the following article: Makkonen, I. & Hakala, M. & Puska, Martti J. 2006. Modeling the momentum distributions of annihilating electron-positron pairs in solids. Physical Review B. Volume 73, Issue 3. 035103/1-12. ISSN 1550-235X (electronic). DOI: 10.1103/physrevb.73.035103, which has been published in final form at http://journals.aps.org/prb/abstract/10.1103/PhysRevB.73.035103. en
dc.subject.other Physics en
dc.title Modeling the momentum distributions of annihilating electron-positron pairs in solids en
dc.type A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä fi
dc.description.version Peer reviewed en
dc.rights.holder American Physical Society (APS)
dc.contributor.school Perustieteiden korkeakoulu fi
dc.contributor.school School of Science en
dc.contributor.department Teknillisen fysiikan laitos fi
dc.contributor.department Department of Applied Physics en
dc.subject.keyword positron annihilation en
dc.subject.keyword density-functional theory en
dc.subject.keyword defects en
dc.subject.keyword semiconductors en
dc.identifier.urn URN:NBN:fi:aalto-201509164291
dc.type.dcmitype text en
dc.identifier.doi 10.1103/physrevb.73.035103
dc.type.version Final published version en


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