Prediction of fundamental properties of Be-B-Ta based novel ternary compounds from first-principles calculations

Enamul Haque; M. Anwar Hossain; Catherine Stampfl

doi:10.1103/PhysRevMaterials.3.084804

paper

Prediction of fundamental properties of Be-B-Ta based novel ternary compounds from first-principles calculations

arXiv:1903.03271 · doi:10.1103/PhysRevMaterials.3.084804

Abstract

Be-B/B-Ta based compounds are very attractive to researchers because of their high density and ultra-hardness. But ternary Be-B-Ta compounds are neither synthesized nor predicted. In this paper, variable composition evolutionary crystal structure prediction calculations based on first-principles method have been performed to find the stable crystal structure containing Be-B-Ta at ambient condition. The predicted five compounds BeB $_{2}$ Ta, BeB $_{3}$ Ta $_{2}$ (high-pressure phase), BeBTa, BeBTa $_{2}$ , and Be $_{2}$ B $_{2}$ Ta have been found to be highly dense and very hard materials. All these compounds are metallic and spin-orbit coupling (SOC) effect is significant in them. Only two of them (BeB $_{2}$ Ta and Be $_{2}$ B $_{2}$ Ta) have been found to be superconductors within Migdal-Eliashberg theory. The calculated critical temperature including SOC effect is 8 and 9 K for BeB $_{2}$ Ta and Be $_{2}$ B $_{2}$ Ta, respectively. Because of their energetic and dynamic stability, these compounds might be favorable to synthesize in the laboratory.

28 pages, 9 figures