Electronic and mechanical properties of fl-Cu6 Sn5 doped by Ni: A first-principles study

In this paper, based on the crystallographic characteristics of fl-Cu6Sn5, 6 Sn 5 , a 1x1x5 supercell was constructed, and Ni atom was doped into each of the eight Cu2 sites respectively. The electrical and mechanical properties of fl-Cu6Sn5 6 Sn 5 doped with Ni atom at Cu2 site were calculated by first principles method. The single-crystal elastic constants and poly-crystalline elastic moduli were acquired by using Voigt-Reuss-Hill approximations. The elastic anisotropies of the doping systems were characterized by a three-dimensional (3D) surface constructions and two-dimensional (2D) plane projections. The results show that the doping of Ni can reduce the elastic anisotropy of fl-Cu6Sn5. 6 Sn 5 . The most significant decrease in elastic anisotropy is observed when Ni is doped at the Ni-1 position in fl-Cu6Sn5. 6 Sn 5 . The doping of Ni can also alter the fracture toughness of fl-Cu6Sn5. 6 Sn 5 . Adding Ni to some Cu2 sites can increase the shear resistance of fl-Cu6Sn5. 6 Sn 5 . Through electronic structure calculations, it is found that the doping of Ni alters the electronic structure and stability of fl-Cu6Sn5. 6 Sn 5 . Specifically, Ni-d orbitals hybridize with Sn-p orbitals, which in turn increases the peak value near-1.54 eV. When Ni is doped at the Ni-3 position, the stability of fl-Cu6Sn5 6 Sn 5 increases the most; conversely, when Ni is doped at the Ni-1 position, the stability of fl-Cu6Sn5 6 Sn 5 decreases the most.