Parameter-Free Gradient Correction for Positron States in Oxides

摘要

Recently, the theory of gradient-corrected electron-positron correlations in solids was improved and extended in order to avoid the adjustable, empirical parameter 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.