Topology of charge density and elastic anisotropy of Ti₃SiC₂polymorphs

Using an all-electron, full potential first-principles method, we have investigated the topology of charge density and elastic anisotropy of Ti₃SiC₂polymorphs comparatively. By analyzing the charge density topology, it was found that the Ti–Si bonds are weaker in β than in α, resulting in a destabilizing effect and lower Young’s modulus in directions betweenaandcaxes for β. On the other hand, the Si–C bonds (absent in α) are formed in β in thecdirection. The formation of the Si–C bonds not only mitigates the destabilizing effect of the weaker Ti–Si bonds, but also results in larger Young’s modulus in thecdirection. In contrast to the high elastic anisotrophy, the elastic anisotropy of Ti₃SiC₂is very low.