Volume 75, Number 3, August 2006
|Page(s)||475 - 481|
|Section||Condensed matter: electronic structure, electrical, magnetic, and optical properties|
|Published online||05 July 2006|
Positron-electron annihilation rates in an electron gas studied by variational Monte Carlo simulation
Polish Academy of Sciences, W. Trzebiatowski Institute for Low Temperature and Structure Research - P.O. Box 1410, 50-950 Wrocław 2, Poland
Accepted: 19 June 2006
The studies of the electron-positron (e-p) interaction in condensed matter using the quantum Monte Carlo (QMC) simulations brought only fragmentary or incorrect results and have been suspended for a longer time. In the present work using the variational quantum Monte Carlo (VQMC) method correct and reasonable annihilation rates for a positron in an electron gas (EG) in a wide range of electron densities have been obtained. This has been achieved owing to an appropriate construction of the trial function which takes into account the 3-particle correlations (i.e. the dependence of the e-e interaction on the distance from the positron) and Friedel oscillations of the e-p correlation function. The annihilation rates have been found by “direct determination" of e-p contact densities on the basis of the variational trial function. We also have found the scheme for calculating of the momentum-dependent enhancement factors (MDEF), quantities not achievable within the MC method until now.
PACS: 71.60.+z – Positron states / 02.70.Ss – Quantum Monte Carlo methods / 71.10.Ca – Electron gas, Fermi gas
© EDP Sciences, 2006
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