Temperature dependence of positron vacancy trapping in the Feynman polaron model

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Abstract
The possibility of a temperature dependent positron trapping rate by vacancies due to diffusive like positron motion is investigated. The Feynman model of a particle harmonically bound to its previous position is used to model the positron-phonon interaction. This model, valid over a wide range of coupling strengths in the polaron problem, allows the positron motion to be varied continuously from a nearly free particle limit to very strong positron-phonon scattering. Calculations to lowest order in the trapping potential show no evidence of a temperature dependent trapping rate if the traps are deep, even for unphysically strong coupling.