First-principles calculations of structural, electronic, elastic and thermal properties of phase M2SiC (M=Ti, V, Cr, Zr, Nb, Mo, Hf, Ta and W)
(1. Laboratory of Studies of Surfaces and Interfaces of Solids Materials, University of Setif 1, Setif 19000, Algeria;
2. Research Unit on Emerging Materials, University of Setif 1, Setif 19000, Algeria;
3. Department of Physics, University of Bordj Bou-Arreridj, 34000, Algeria;
4. Laboratory for Developing New Materials and their Characterization, Department of Physics,
Faculty of Science, University of Setif 1, Setif 19000, Algeria)
2. Research Unit on Emerging Materials, University of Setif 1, Setif 19000, Algeria;
3. Department of Physics, University of Bordj Bou-Arreridj, 34000, Algeria;
4. Laboratory for Developing New Materials and their Characterization, Department of Physics,
Faculty of Science, University of Setif 1, Setif 19000, Algeria)
Abstract: The structural, electronic and elastic properties of the M2SiC phases were studied, where M are 3d, 4d, and 5d early transition metals. The valence electron concentration (VEC) effect of Ti, V, Cr, Zr, Nb, Mo, Hf, Ta and W on these properties was examined. The C44 saturates for a VEC value in surrounding of 8.5 for each serie. Hf-s, Ta-s and W-s electrons mainly contribute to the density of states at the Fermi level, and should be involved in the conduction properties. The distortion increases with increasing VEC and decreasing kc/ka factor except for the series M=Ti, V and Cr, where it is lower at the VEC value of 8.5 (it follows a parabolic variation). The M2SiC was characterized by a profound anisotropy for the shear planes and compressibility in the direction is higher than that along the cone except for W2SiC, where it is lower.
Key words: ternary carbides; ab initio calculation; crystal structural; electronic structure