Parameter-Free Gradient Correction for Positron States in Oxides

Recently, the theory of gradient-corrected electron-positron correlations in solids was improved and extended in order to avoid the adjustable, empirical parameter α which is now part of theory and a smooth function of the electron density.This new, parameter-free approach is applied to selected oxides in order to discuss their interstitial space morphology reflected by the positron charge distribution. In addition, the positron lifetime and affinity are calculated using a highly precise computational method. An attempt is made to correlate these quantities with the volume of the reduced formula unit.The results for some oxides - such as Li-ion battery cathode materials and high temperature superconductors - are discussed in detail and prospects for future experiments are given.

First-Principles Study on Positron States at Li-Adsorbed Al(100) Surfaces: Effect of Electron-Positron Correlation

We investigated positron states at Li-adsorbed Al(100) surfaces using \textit{ab-initio} two-component density functional theory. The results thus obtained by using semi-local electron-positron (e-p) correlation functionals with the generalized gradient approximation well reproduce the experimental results, showing that reliable e-p correlation functionals are needed to properly describe the various properties of positron surface state.