Ab initio Study of the Temperature Dependence of the EFG at Cd Impurities in Rutile TiO2

Abstract

We report a FLAPW study of the temperature dependence of the electric-field gradient (EFG) tensor at Cd impurities replacing cations in TiO2. In order to simulate the temperature effect, we considered experimental temperature-dependent lattice parameters, and we obtain the structural relaxations introduced by the Cd impurities and the EFG tensor for each lattice parameters set. We found that these relaxations depends on the temperature and are at the origin of the strong temperature dependence of the EFG. We also showed that a correct description of the electronic structure of the impurity-host system is essential for the description of the EFG and its temperature dependence.