Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China.
Physics Department, Sichuan Normal University, Chengdu 610068, China.
J Chem Phys. 2013 Dec 21;139(23):234503. doi: 10.1063/1.4846855.
The first-principles calculations are employed to provide a fundamental understanding of the structural features and relative stability, mechanical and electronic properties, and possible reactive route for chromium triboride. The predicted new phase of CrB3 belongs to the rhombohedral phase with R-3m symmetry and it transforms into a hexagonal phase with P-6m2 symmetry at 64 GPa. The mechanical and thermodynamic stabilities of CrB3 are verified by the calculated elastic constants and formation enthalpies. Also, the full phonon dispersion calculations confirm the dynamic stability of predicted CrB3. Considering the role of metallic contributions, the calculated hardness values from our semiempirical method for rhombohedral and hexagonal phases are 23.8 GPa and 22.1 GPa, respectively. In addition, the large shear moduli, Young's moduli, low Poisson's ratios, and small B∕G ratios indicate that they are potential hard materials. Relative enthalpy calculations with respect to possible constituents are also investigated to assess the prospects for phase formation and an attempt at high-pressure synthesis is suggested to obtain chromium triboride.
采用第一性原理计算方法，深入研究了三硼化铬的结构特征、相对稳定性、力学和电子性质，以及可能的反应途径。预测的 CrB3 新相属于三方相，具有 R-3m 对称性，在 64 GPa 下转变为六方相，具有 P-6m2 对称性。通过计算弹性常数和形成焓验证了 CrB3 的力学和热力学稳定性。此外，全声子色散计算也证实了预测的 CrB3 的动力学稳定性。考虑到金属贡献的作用，我们用半经验方法计算出的三方相和六方相的硬度值分别为 23.8 GPa 和 22.1 GPa。此外，大的剪切模量、杨氏模量、低泊松比和小的 B∕G 比表明它们是潜在的硬质材料。还研究了与可能的组成物的相对焓计算，以评估相形成的前景，并建议进行高压合成以获得三硼化铬。
