First principles study on geometry structure, elastic property and electronic structure of La-doped Mg₂Si

Abstract

The geometrical structure, elastic properties and electronic structure of Mg2Si doped with lanthanum (La) were calculated and analyzed by using the first-principles plane wave pseudopotential method of density functional theory. Firstly, combined with the results of the formation of erbium and Born mechanical stability, it can be seen that Mg8Si4La and Mg8Si3La do not exist stably after doping with rare earth element La. La-doped Mg2Si preferentially occupies the position of the system Mg atom; Secondly, the bulk modulus (B), the shear modulus (G), Young's modulus (E), Poisson's ratio (ν), and anisotropy coefficient (A) of the crystal were calculated that the intrinsic Mg2Si is a brittle phase, while Mg7Si4La is a ductile phase. The doping of La can improve the ductility of Mg2Si. Finally, the calculation of density of states, Mulliken population and charge differential density show that Fermi surface is deviated from the high-energy region after doping with rare earth, and enters the conduction band, which improves the conductivity of Mg2Si.

Keywords

• first principles
• rare earth element la
• mg₂si
• elastic property
• electronic structure