ELECTRONIC-STRUCTURE AND ELECTRIC-FIELD GRADIENTS IN 2H-TAS2, LITAS2 AND SNTAS2

The electronic properties of the layered compound 2H-TaS2 and its Li and Sn intercalates 2H-LiTaS2 and 2H-SnTaS2 are determined from first principles using the full potential linearized augmented plane wave (LAPW) method. Energy band structures, total and partial densities of states, partial charges and electron densities are presented and the bonding mechanism in these compounds is discussed. Using self-consistent electron densities, the electric field gradients (EFG) at all nuclear positions are determined without further approximations and a detailed explanation of the origin of the EFG is given. Good agreement with experimental EFCS is found. From the contact densities at the Ta nuclei, the isomer shifts and a new interpretation of the Mossbauer data for LiTaS2 are presented.