Benchmarking Full-Potential Linearized Augmented Plane Wave (FLAPW) Method for Determination of Muon Stopping Sites in LiF

Muon stopping sites in Lithium Fluoride have been determined based on the minimum electrostatic potential calculation using density functional theory implemented in the full-potential linearized augmented planewave method. The isosurface of the electrostatic potential obtained in our calculation is similar to the calculation obtained by using pseudopotential-based plane wave (PPPW) method reported by Bernadini et al. [Physical Review B, 87 (2013) 115148]. This yields to the two possible muon sites inside the cage structure of Li-F forming tetrahedral coordination. One of the muon sites is located at the center of the tetrahedral while the other is at the equivalent site of the tetrahedral. In spite of the similar isosurface results, our global minimum is found at the center of the tetrahedral in contrast to the previous result obtained at the tetrahedral sites. The strategy to determine the muon possible sites based on the minimum of the total energy of the system will also be considered including the muon sites position between the two fluorine ions (F-).