Gradient correction scheme for bulk and defect positron states in materials: New developments

13th International Workshop on Slow Positron Beam Techniques and Applications

Kuriplach, J.^1 ; Barbiellini, B.^2

Department of Low Temperature Physics, Faculty of Mathematics and Physics, Charles University in Prague, V Holeovikách 2, CZ-18000 Prague, Czech Republic^1

Department of Physics, Northeastern University, Boston, MA 02115, United States^2

关键词: Correction schemes;    Generalized gradient approximations;    Hyper netted chains;    Positron lifetime;    Positron state;    Quantum monte carlo;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/505/1/012040/pdf
DOI  :  10.1088/1742-6596/505/1/012040

来源: IOP

【 摘 要 】

As local density approximation positron calculations systematically underestimate positron lifetimes when they are compared with their experimental counterparts, the generalized gradient approximation (GGA) for positrons was introduced in the 1990s, in analogy with the GGA for electrons. New developments in the GGA for positrons are summarized and presented here and it is also discussed how they affect and possibly improve calculated positron lifetimes. In particular, these new GGA approaches are based on the recent perturbed hypernetted-chain and quantum Monte Carlo results.