Theoretical investigations of NiTiSn and CoVSn compounds

• Published in: The Journal of physics and chemistry of solids Vol. 73; no. 8; pp. 975 - 981
• Main Authors: Hichour, M., Rached, D., Khenata, R., Rabah, M., Merabet, M., Reshak, Ali H., Bin Omran, S., Ahmed, R.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.08.2012
• Subjects: C. Ab initio calculations; D. Electronic structure; Debye temperature; Elastic constants; Electronics; Energy bands; Gaps; Mathematical analysis; Modulus of elasticity; Orbitals; D. Electronic structure; C. Ab initio calculations
• ISSN: 0022-3697; 1879-2553
• DOI: 10.1016/j.jpcs.2012.03.014

The structural, elastic and electronic properties of NiTiSn and CoVSn half-Heusler compounds have been calculated using the full-potential linear muffin-tin orbital (FP-LMTO) method. The computed equilibrium lattice constants are in excellent agreement with the available experimental and theoretical data. The elastic constants Cij are calculated using the total energy variation with strain technique. The polycrystalline elastic moduli (namely: the shear modulus, Young's modulus, Poisson's ratio, Lamé's coefficients, sound velocities and the Debye temperature) were derived from the obtained single-crystal elastic constants. The ductility mechanism for the studied compounds is discussed via the elastic constants Cij and their related parameters. The electronic band structure calculations show that the conduction band minimum (CBM) is located at the X point for both compounds, whereas the valence band maximum (VBM) is located at the Г point for NiTiSn and at the L point for CoVSn, resulting in indirect energy band gaps of 0.46 and 0.75eV for NiTiSn and CoVSn, respectively. The pressure and volume dependences of the energy band gaps have been calculated.