反键分子轨道
材料科学
亚稳态
锡
从头算量子化学方法
焓
金属
从头算
金属键合
费米能级
结构稳定性
环境压力
热力学
结晶学
化学物理
冶金
化学
电子
分子
物理
有机化学
结构工程
量子力学
原子轨道
工程类
作者
Peiju Hu,Xing Xie,Huafeng Dong,Minru Wen,Le Huang,Zhongfei Mu,Fugen Wu,Chengyong Wang
摘要
High-hardness metal compounds have huge potential applications in multifunctional devices used under extreme conditions. Here, an ab initio evolutionary algorithm was used to systematically search for structures in the Re3C system with high hardness and metallicity under the pressure of 0–300 gigapascal (GPa). We discovered a structure (namely, C2/m) with the lowest enthalpy at 154 GPa and two metastable phases (namely, P63/mmc and C2/m-α), which could maintain thermodynamic and mechanical stability at zero pressure, and they could be quenched to ambient conditions. More importantly, the hardness of the metal compounds (21.4 GPa for C2/m, 25.2 GPa for P63/mmc) exceeds that of TiN (18.7 GPa), the material for commercial machine tools. In addition, our analysis shows that the coexistence of Re–C bond and Re–Re bond with strong coupling, and avoiding the antibonding state of 5d-electron of Re–Re bond near the Fermi level, could be the reasons why the structure has high hardness and metal properties at the same time.
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