First-principles study of the structural and elastic properties of Cr2AlX (X=N, C) compounds
| Autor: | Shouxin Cui, Dong-Qing Wei, Haiquan Hu, Wenxia Feng, Zizheng Gong |
|---|---|
| Rok vydání: | 2012 |
| Předmět: |
Bulk modulus
Materials science Charge density Thermodynamics Condensed Matter Physics Electronic Optical and Magnetic Materials Inorganic Chemistry Shear modulus Pseudopotential symbols.namesake Crystallography Chemical bond Materials Chemistry Ceramics and Composites Density of states symbols Density functional theory Physical and Theoretical Chemistry Debye model |
| Zdroj: | Journal of Solid State Chemistry. 191:147-152 |
| ISSN: | 0022-4596 |
| DOI: | 10.1016/j.jssc.2012.03.014 |
| Popis: | The structural, electronic and elastic properties of Cr 2 Al X , with X =N, C, have been investigated at the density functional theory level by applying a plane-wave pseudopotential approach. The band structure and density of states reveal the metallic features of Cr 2 Al X . The total and projected density of states indicate that the bonding is achieved through a hybridization of Cr 3 d states with Al and X -atom p states. The Cr 3 d – X 2 p bonds are lower in energy and are stiffer than Cr 3 d –Al 3 p bonds. The charge density distributions indicate that there exist soft Cr—Al and relatively strong Cr– X covalent bonds, which might be responsible for their hardness. The elastic constants were obtained in the pressure range 0–100 GPa, and satisfy the stability conditions for hexagonal crystal, which indicates that these two compounds are stable in the pressure regime studied. By analyzing bulk modulus to shear modulus ratio and Cauchy pressure, Cr 2 AlC is predicted to be brittleness and Cr 2 AlN is ductile. The Debye temperature was obtained from the average sound velocity. |
| Databáze: | OpenAIRE |
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