New crystal structure and physical properties of TcB from first-principles calculations

• 作者: 张刚台 白婷婷 赵亚儒 闫海燕
• 来源期刊: 中国物理B（英文版）
• 关键词: TcB structure prediction ultra-incompressible material thermodynamic properities
• 年，卷（期）: 2015,（10）
• 页码范围: 106104-1-106104-7
• 页数: 1页
• 语种: 英文
• DOI: 10.1088/1674-1056/24/10/106104

摘要

By combining first-principles calculations with the particle swarm optimization algorithm, we predicted a hexagonal P ˉ3m1 structure for TcB, which is energetically more favorable than the previously reported WC-type and Cmcm structures. The new phase is mechanically and dynamically stable, as confirmed by its phonon and elastic constants calculations. The calculated mechanical properties show that it is an ultra-incompressible and hard material. Meanwhile, the elastic anisotropy is investigated by the shear anisotropic factors and ratio of the directional bulk modulus. Density of states analysis reveals that the strong covalent bonding between Tc and B atoms plays a leading role in forming a hard mate-rial. Additionally, the compressibility, bulk modulus, Debye temperature, Gr ¨uneisen parameter, specific heat, and thermal expansion coefficient of TcB are also successfully obtained by using the quasi-harmonic Debye model.