Electron-positron Car-Parrinello methods: Self-consistent treatment of charge densities and ionic relaxations

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© 1995 American Physical Society (APS). This is the accepted version of the following article: Puska, M. J. & Seitsonen, Ari P. & Nieminen, Risto M. 1995. Electron-positron Car-Parrinello methods: Self-consistent treatment of charge densities and ionic relaxations. Physical Review B. Volume 52, Issue 15. 10947-10961. ISSN 1550-235X (electronic). DOI: 10.1103/physrevb.52.10947, which has been published in final form at http://journals.aps.org/prb/abstract/10.1103/PhysRevB.52.10947.

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Journal ISSN

Volume Title

School of Science | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

Date

1995

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Mcode

Degree programme

Language

en

Pages

10947-10961

Series

Physical Review B, Volume 52, Issue 15

Abstract

A calculation method based on the two-component density-functional theory is presented for electron systems with a localized positron. Electron-ion and positron-ion interactions are described by norm-conserving pseudopotentials and full ionic potentials, respectively. The electron and positron densities are solved self-consistently using a plane-wave expansion for electron and a real-space grid method for positron wave functions, respectively. The forces on ions exerted by a positron trapped at an open-volume defect and the ensuing ionic relaxations are determined using first-principles methods. In the case of semiconductors, the self-consistent solution of electron and positron densities as well as the ionic positions are found to depend strongly on the treatment of the electron-positron correlation in constructing the effective potentials. We consider several approximations to the correlation energy while demonstrating the method by calculations for a positron trapped by a Ga vacancy in GaAs. Especially, the effects on the observable positron annihilation characteristics, i.e., positron lifetimes, core annihilation line shapes, and two-dimensional angular correlation maps are discussed.

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Keywords

localized positrons, electron systems, density-functional theory

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Citation

Puska, M. J. & Seitsonen, Ari P. & Nieminen, Risto M. 1995. Electron-positron Car-Parrinello methods: Self-consistent treatment of charge densities and ionic relaxations. Physical Review B. Volume 52, Issue 15. 10947-10961. ISSN 1550-235X (electronic). DOI: 10.1103/physrevb.52.10947.