Hf<sub>2</sub>Ni Compound Investigation: Electronic Structure and Electric Field Gradient

Abstract

The electronic structure of the Hf2Ni intermetallic compound has been obtained using the first-principle full-potential (FP) linear-muffin- tin-orbital (LMTO) method in the atomicsphere approximation (ASA). The electric field gradient (EFG) tensor is calculated for both HI' and Ni sites and compared with the experiment. The theoretical results show that the EFG is determined dominantly by the p electrons. 1. Introd uction The interaction between the nuclear quadrupole moment and the electric field gradient (EFG) at the atomic site with noncubic point symmetry can be determined by various hyperfine interaction measurements, such as: perturbed angular correlation (PAC), perturbed angular distribution, and nuclear magnetic resonance (NMR). These methods were used widely to get information about surfaces, impurities, and vacancy related defects. A lot of experimental investigations of EFG in complex compounds with many atoms per primitive cell have appeared in recent years. Some of them have been devoted to the timedifferential perturbed angular correlation (TDPAC) measurements of nuclear quadrupole interactions in the ordered intermetalic compounds of transition metal Hf. It was shown that EFG reveals interesting properties in these compounds. These compounds represent a challenge for the theory due to their complexity. The explanation of the origin and the magnitude of EFG in one of them, e.g. Hf2Ni, is the subject of the present theoretical investigation.