Accurate theoretical prediction on positron lifetime of bulk materials

TL;DR

This paper evaluates and improves the accuracy of first-principles theoretical predictions of positron lifetime in bulk materials, achieving a new reliability level and proposing a superior GGA correlation scheme.

Contribution

It introduces a new GGA correlation form that enhances the accuracy of positron lifetime predictions across various bulk materials.

Findings

Original GGA overestimates gradient effects.

Model agrees with data within noise levels.

New GGA form outperforms previous models.

Abstract

Based on the first-principles calculations, we perform an initiatory statistical assessment on the reliability level of theoretical positron lifetime of bulk material. We found the original generalized gradient approximation (GGA) form of the enhancement factor and correlation potentials overestimates the effect of the gradient factor. Furthermore, an excellent agreement between model and data with the difference being the noise level of the data is found in this work. In addition, we suggest a new GGA form of the correlation scheme which gives the best performance. This work demonstrates that a brand-new reliability level is achieved for the theoretical prediction on positron lifetime of bulk material and the accuracy of the best theoretical scheme can be independent on the type of materials.