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

TL;DR

This study predicts stable Be-B-Ta ternary compounds with high density and hardness using first-principles calculations, identifying potential superconductors with specific critical temperatures.

Contribution

First-principles crystal structure prediction of stable Be-B-Ta compounds, revealing their properties and potential for synthesis and superconductivity.

Findings

Five stable Be-B-Ta compounds identified

Two compounds are superconductors with Tc of 8 and 9 K

Compounds are metallic with significant SOC effects

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.