高压下ZrB3与NbB3力学性质的第一性原理研究

First principles studies on mechanical properties of ZrB3 and NbB3 under high pressure

摘要:

此文用密度泛函理论的赝势平面波方法的第一性原理研究了过渡金属化合物ZrB3与NbB3（m-AlB2、OsB3和MoB3结构）在高压下的力学性质和电子结构特点, 获得了在常压下, m-AlB2是最稳定的结构,当压强升高到40 GPa时发生相变,高压下最稳定是OsB3结构.m-AlB2-NbB3具有最大的剪切模量204 Gpa, 最高的德拜温度921 K和最大的硬度值27.3 Gpa, 属于潜在的超不可压缩材料. MoB3-NbB3、OsB3-NbB3 和m-AlB2-ZrB3的硬度值分别达到了24.9 GPa 、 22.6 GPa和19.8 Gpa. 它们的电子态主要是由M-4d态和B-2p态杂化叠加形成的, 在费米能级处取值均不为零, 故这些化合物都具有金属性等有益结果.

Abstract:

The mechanical properties and the electronic structures of transition metal compounds ZrB3 and NbB3 (m-AlB2, OsB3 and MoB3 structures) under high-pressure are studied by using the first-principles within density functional theory. It was found that m-AlB2 is the most stable structure under normal pressure. The pressure-induced phase transition occurs at the pressure of 40 Gpa, OsB3 structure becomes the most stable one under high pressure. m-AlB2-NbB3 has a maximum shear modulus of 204 GPa, the highest Debye temperature of 921 K, and the highest hardness of 27.3 GPa. The harnesses are estimated to be 24.9 GPa, 22.6 GPa and 19.8 GPa for MoB3-NbB3, OsB3-NbB3 and m-AlB2-ZrB3, respectively. The calculated density of states (DOS) illustrated that the electronic structures of considered compounds are governed by the strong hybridization between M-4d and B-2p states. All compounds are metallic.