Elastic properties and electronic structures of NaAlSi ternary obtained with first-principle calculations

Abstract

First-principle calculations were carried out on the ternary of sodium aluminium silicide to evaluate the elastic properties and electronic structures within the framework of the density functional theory. Six independent elastic constants were obtained from the coefficients of the polynomials determined by non-linear least squares fitting of the energy-strain functions, and the elastic parameters of the corresponding polycrystalline aggregates were estimated from the calculated single crystal elastic constants. The electronic structure and charge density distribution were explored to analyse and explain the nature of chemical bonding. The results showed that the sodium aluminium silicide compound is a mechanically stable and brittle material with a metallic character. The nature of the bonds formed a layer structure, with a layer of covalent bonding between the Si and Al atoms alternating with a Na atom layer which bonded the Al–Si layer by ionic interaction.

Keywords:

• First-principle calculation
• Sodium aluminium silicide
• Elastic properties
• Electronic band structure
• Fermi surface