A calculation of the annihilation characteristics of positrons trapped at metal surfaces

Brown, AP; Walker, A.B.; West, R N

doi:10.1088/0305-4608/17/12/021

Cited by 25 publications

(3 citation statements)

References 15 publications

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“…The calculations Puska and Nieminen, 1983b) (Lang and Kohn, 1970) was fitted to give the experimental electron work function (Brown et al , 1987) for Al. The potential sensed by a positron was also adjusted by a step potential at the surface so that the calculations could give the experimental positron work function.…”

Section: Defects In Semiconductorsmentioning

confidence: 99%

Theory of positrons in solids and on solid surfaces

1994

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Various experimental methods based on positron annihilation have evolved into important tools for researching the structure and properties of condensed matter. In particular, positron techniques are useful for the investigation of defects in solids and for the investigation of solid surfaces. Experimental methods need a comprehensive theory for a deep, quantitative understanding of the results. In the case of positron annihilation, the relevant theory includes models needed to describe the positron states as well as the different interaction processes in matter. In this review the present status of the theory of positrons in solids and on solid surfaces is given. The review consists of three main parts describing (a) the interaction processes, {b) the theory and methods for calculating positron states, and {c)selected recent results of positron studies of condensed matter. CONTENTS

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Section: Defects In Semiconductorsmentioning

confidence: 99%

Theory of positrons in solids and on solid surfaces

1994

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“…Most recently, Brown and co-workers [12] also considered the present problem. Their angular correlation curves were obtained using an independent particle model (IPM) and are quite isotropic, but they obtained the perpendicular FWHM larger than the parallel FWHM, contrary to our present results.…”

Section: Introductionmentioning

confidence: 99%

“…Although the MDA includes electron-positron correlations, it is not suitable for the case of fast spatial variations in the electron density near the surface [ 141. The local momentum distribution approximation used in [12] with a local Fermi momentum does not represent correctly the local electronic momentum distribution. This is so since the local electron momentum distribution does not only depend on the local electron density but also depends on the total profile of the electron density, such as the gradient of the density.…”

Section: Introductionmentioning

confidence: 99%

Calculation of the angular correlation and the lifetime of positron surface states on metal surfaces

Lou¹,

Gu²,

Jia-Lin³

et al. 1989

J. Phys.: Condens. Matter

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Using a potential model for the surface of a metal and the revised Brandt-Reinheimer enhancement factor r ( n ) , we have calculated the electron wavefunction, the two-dimensional angular correlation and the lifetime of 2y annihilation from the AI( loo), A1(110), Al(111) and Cu(121) surfaces. We conclude that (i) the momenta of the electrons are filtered by the suridce potential; (ii) the momentum distribution of 2y annihilation is greatly constricted for both the parallel and perpendicular directions to the surface; (iii) it is possible to obtain simultaneously the observed isotropic angular correlation curve and the long lifetime of the positron surface state; and (iv) within a reasonable range of our model parameters, the isotropy of the angular correlation curve is rather insensitive to the parameter values. Our results are consistent with experiment.

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Positron and Positronium Momentum Spectroscopy in Solids: An Overview

Berko

1989

Momentum Distributions

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A calculation of the annihilation characteristics of positrons trapped at metal surfaces

Cited by 25 publications

References 15 publications

Theory of positrons in solids and on solid surfaces

Theory of positrons in solids and on solid surfaces

Calculation of the angular correlation and the lifetime of positron surface states on metal surfaces

Positron and Positronium Momentum Spectroscopy in Solids: An Overview

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