Electronic structure and hyperfine interactions of 3d transition element ions in CdTe

Abstract

We present ab initio total energy calculations for the 3d transition metal (TM) defects on the Cd site in CdTe. Our calculations are performed using the linear muffin-tin orbital method in the atomic sphere approximation (LMTO-ASA) and are aimed at the theoretical calculation of hyperfine and ligand hyperfine interactions (HFIs). Our calculations show that although the 3d TMs are covalently bound to the nearest-neighbour (NN) Te ligands, the HFI with these Te ligands is very small and corresponds to of a spin at most. The ligand HFI with the next-nearest-neighbour (NNN) Cd nuclei is even smaller in most cases than that with the Te ligand nuclei. We show for the case of that it is not the small natural abundance of paramagnetic Te nuclei which prevents the experimental observation of the ligand HFI with the nuclei, but rather the fact that the HFI lines for the interaction with the NN ligand nuclei coincide with interactions with the NNN and ligand nuclei. This prevents the observation of larger HFIs with the NN Te ligands although the smaller HFI with the NNN Cd ligands is clearly resolved.