Screening of positrons in semiconductors and insulators

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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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1989-04-15

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University of Jyväskylä
Department of Applied Physics

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en

Pages

14
7666-7679

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Physical Review B, Volume 39, issue 11

Abstract

Theoretical models are presented for the enhancement of the electron density at a positron in a semiconductor or insulator host. The model better suited for typical semiconductors is based on the many-body theory for the screening of a positron in electron gas. The starting point of the model for insulators is the atomic polarizability. The common parameter in both models is the high-frequency dielectric constant. Moreover, the enhancement depends on the ambient electron density in the semiconductor model and on the unit-cell volume in the insulator model. With use of the models developed, positron lifetimes in perfect semiconductor and insulator crystals have been calculated. In the calculations, three-dimensional electron densities and electrostatic potentials are obtained by atomic superposition and the fully three-dimensional positron wave functions are solved by a relaxation method. The calculated positron lifetimes agree with the experimental ones within a few picoseconds. Moreover, we have used the model to predict lifetimes of positrons trapped by lattice defects such as vacancies and vacancy clusters.

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DOI

10.1103/PhysRevB.39.7666

Citation

Puska , M J , Mäkinen , S , Manninen , M & Nieminen , R 1989 , ' Screening of positrons in semiconductors and insulators ' , Physical Review B , vol. 39 , no. 11 , pp. 7666-7679 . https://doi.org/10.1103/PhysRevB.39.7666

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https://urn.fi/URN:NBN:fi:aalto-201805222444

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[article-cris] Perustieteiden korkeakoulu / SCI