CoSb_2结构5d过渡金属二氮化物力学性质的第一性原理研究

First-principles study on 5d transition metal dinitrides with CoSb_2 structure

基于密度泛函理论平面波赝势的第一性原理方法,对具有CoSb2结构5d过渡金属二氮化物TMN2(TM=Hf、Ta、W、Re、OsI、r、Pt、Au)的晶格常数、电子结构和力学性能进行了计算。计算结果表明,对于该结构的二氮化物,除AuN2外,均同时满足热力学和机械稳定性标准;其中OsN2具有最高的体弹性模量和剪切模量分别为418和257GPa;态密度分析表明,过渡金属原子的5d轨道与氮原子的2p轨道之间发生了强烈的杂化现象,二者之间形成了较强共价键。

First-principles calculations were performed to investigate the heat of formation, elastic constant and density of states of transition metal dinitrides TMN2 （TM=Hf,Ta,W, Re, Os,Ir, Pt and Au） in P21/c space group. Our calculation results indicate that HfN2 ,TAN2 ,ReNz ,OsN2,IrN2 and PtN2 are thermodynamically and mechanically stable. Among them,OsN2 has the highest bulk modulus （418GPa） and shear modulus （257GPa）. Significant hybridization between TM5d and N2p can be seen from DOS and PDOS.