Electronic properties of Hf2X intermetallic compounds (X = Al, Si, Ni, Ga and Ge)

The electric field gradient (EFG) parameters were calculated for the binary system Hf(2)X (X = Al, Si, Ni, Ga and Ge), using the full-potential linear augmented plane wave method, applying the generalized gradient approximation. The major contribution to the EFG value in these compounds comes from the p-p contribution next to the probe nucleus. The only other significant contribution is a d-d contribution to the nickel site in Hf(2)Ni, arises from the broad spatial distribution of the nickel 3d electrons. The similarity in the electronic properties of the Hf(2)X compounds, with the exception of Hf(2)Ni, can be attributed to the resemblance of the crystallographic structure and the alike electronic structure of the X-ligand atom, having one or two p-electrons in the external orbital with close shells below.