First-principles calculations of elastic properties of Cu3Sn superstructure

We report the elastic properties of Cu3Sn superstructure based on first-principles calculations. Polycrystalline Young’s modulus and Poisson’s ratio are deduced from the calculated elastic stiffness. The calculations of electronic structures with the principal strains along different directions unravel the electronic nature of anisotropic elasticity of Cu3Sn. Weak Sn–Cu bonding in Cu3Sn suggests that Sn atoms are the dominant diffusion species, revealing the mechanism of vacancy formation within the Cu3Sn superstructure.