LAUSR

Abstract This article reports a newly discovered crystal structure of LiBeF3 from approximately 700 candidate structures by means of high-throughput DFT (Density Functional Theory) screening. The lowest-energy structure is monoclinic with the P2/c symmetry and its primitive cell contains 100 atoms. The calculated phonon spectrum appears no imaginary modes, which evidences the dynamic stability of this structure. Regarding its thermodynamic stability, the calculated electronic total energy shows that this structure is instable and may decompose into BeF2 and K2BeF4 at T = 0 K; however, above T = 260 K the LiBeF3 structure is stabilized, caused by extra free energy from phonon activation of lattice vibrations. The calculated electronic properties demonstrate that the new structure possesses an indirect band gap larger than 7.7 eV, indicating that the new structure could be a promising candidate for vacuum-ultraviolet-transparent lens in optical lithography steppers used in the semiconductor industry.