Quantum Monte Carlo simulation of positron annihilation radiation in solids
At a Glance
Section titled āAt a Glanceā| Metadata | Details |
|---|---|
| Publication Date | 2020-01-21 |
| Journal | Aaltodoc (Aalto University) |
| Authors | Jan HƤrkƶnen |
Abstract
Section titled āAbstractāIn material studies we use a method called positron annihilation spectroscopy. It is a non-destructive method to study defects and vacancies in solids. It is based on the fact that when a positron and an electron collide, they annihilate and release electromagnetic radiation, or photons, in the form of two observable gamma-quanta. \n \nUpon annihilation, the positron-electron pair also has a momentum. The momentum distribution very much depends on the atomic structure of the sample material. In this project our focus is on the annihilation-pair momentum density (APMD), which is the probability distribution of the momentum in which the positron-electron pair annihilates in the crystal. \n \nInstead of doing experimental measurements, we are concentrating on the simulation of a system of many electrons and one positron in a flawless periodic crystal lattice for carbon, silicon and germanium in the diamond structure. We will computationally approximate the wave function of a system, and with that, we will use the quantum Monte Carlo method to simulate the APMD and compare it with experimental results. \n \nThe main achievements of this project is creating a method to compute the APMD and gathering reference data for it with accurate simulations for well defined atomic structures. This is the first project that involves QMC simulations of non-homogeneous periodic crystal lattices.
Tech Support
Section titled āTech SupportāOriginal Source
Section titled āOriginal Sourceā- DOI: None