BC5力学性质的第一性原理计算

采用平面波赝势密度泛函理论方法对0—60 GPa静水压下BC₅ 六角晶系P3m1和四方晶系I4m2结构的平衡态晶格常数、弹性常数、各向异性以及泊松比与Cauchy扰动进行了研究. 研究结果表明, BC₅的两种结构在高压下是稳定的, 且不可压缩性随着压强的增加而增大. 另外, 对其电子结构也进行了计算, 计算结果表明, BC₅存在一个较宽的带隙, 两种原子间有较强的共价杂化, 材料的性质主要由B的2p¹和C的2p²态电子共同决定. 压强对材料带隙和费米能级附近的态密度几乎没有影响, 只引起微小的漂移, 可推断其很好的高压稳定性.

First-principles calculations for the mechanical properties of BC5

We employ ab initio plane-wave pseudo potential density functional theory to calculate the equilibrium lattice parameters,elastic constants,anisotropies,Poisson’s ratios,and the Cauchy violation under hydrostatic pressures of 0—60 GPa for BC5 with hexagonal P3m1 and tetragonal I4m2 structures.The results show that two structures are stable under high pressure and the incompressibility increases with pressure.In addition,the electron structures,the total and the partial densities of states are also calculated.BC5 is found to be metallic with band gap,unlike other B-C compounds.The material properties of BC₅ are mainly determined by B 2p¹ and C 2p² electronic states together.All these show that BC5 is an unusual super hard material,and it may be a potential candidate for diamond at high temperature.The given density of states indicates the covalent hybridization between B and C atoms in this compound.The pressure slightly influences the density of states and the band gap,indicating stability under high pressure.We also find that pressure has no influence on the density of states near Fermi level and the band gap,except for slight shifts of the bands.It can be further inferred that BC5 will have good stability under high pressure.