Positron states in an electron gas

Abstract

The Green function of a positron in an electron gas is calculated numerically, in a simple approximation which allows for possible binding between the positron and an electron, using statistical Green function techniques in the low-temperature limit. The results suggest that at normal electron densities the positron appears in unbound, relatively free quasiparticle states. For rs approximately=8-60 these quasiparticles can be described approximately as a mixture of a free elementary positron and a bound quasipositronium (Ps*)- electron hole-pair. The model is applied to a positron annihilation calculation.