Prediction of novel ultra-incompressibility compounds TM2B (TM=Mo, W, Re and Os) by first-principles calculations

摘要

Several novel ultra-incompressibility compounds TM2B (TM=Mo, W, Re and Os) have been predicted by means of the first-principles calculations. Those novel compounds were assumed to have a ReB2-type structure [P6(3)/mmc space group (No.194, Z=2), atomic sites: TM 4f (2/3, 1/3, z), B 2c (1/3, 2/3, 1/4)]. We calculated the mechanical properties of the TM2B, and the results reveal that they exhibit brittle behaviour and mechanically stable. The hardness values are 23.8 GPa, 23.3 GPa, 26.6 GPa and 26.3 GPa for Mo2B, W2B, Re2B and Os2B, respectively, which suggests that they are hard materials. Additionally, we found that the anisotropy of Re2B is weaker than the others. Finally, the Mo2B has the highest Debye temperature (905.8 K), while Os2B has the lowest Debye temperature (615.5 K). We hoped that our results can help to offer a theoretical data for future experimental work and application of TM2B.