First-principle investigation on electronic structures and elastic properties of Al-doped MoSi2

The electronic structures and elastic properties of Al-doped MoSi2 were calculated using the plane wave pseudo-potential method based on the density functional theory, in which the generalized-gradient approximation (GGA) was used to describe the exchange-correlation potential. Starting from the elastic constants, bulk modulus, shear modulus, elastic modulus and Poisson ratio of Al-doped MoSi2 were obtained by using the Hill method. The results indicate that conductivity of Al-doped MoSi2 is improved to some extent in comparison with that of pure MoSi2 due to the orbit hybridization of Mo 4d, Al 3p and Si 3p electrons. In addition, calculations show that the elastic modulus and the brittleness of Al-doped MoSi2 are smaller than those of pure MoSi2, which implies that it is feasible to toughen MoSi2 by doping Al. The agreement of the conclusion with experiment shows that the present theory is reasonable.