FP-LAPW study of pure and Ta-doped HfO2

R.E. ALONSO; L. A. ERRICO; E.L. PELTZER Y BLANCÁ; A. LÓPEZ-GARCÍA; A. SVANE; N.E. CHRISTIANSEN

Cataratas del Iguazú

Conferencia; XIV International Conference on Hyperfine Interactions & XVIII International Symposium on Nuclear Quadrupole Interactions; 2007

We present here a first-principles study of the electronic and structural properties of pure and Ta-doped monoclinic HfO2. The full-potential linearized-augmented plane wave method used here allows us to treat the electronic structure of the doped system and the atomic relaxations introduced by the impurities in the host in a fully self-consistent way. In order to approximate the dilution of the Ta impurity we used supercells of increasing size, all containing a single Ta atom, and calculated the self-consistent potential and charge density inside each one. We obtain relaxed structures for different charge states of the impurity and computed the EFGs at the Ta site. We find that EFGs, and also relaxations, are dependent on the charge state of the impurity. The combination of Time Dependant Perturbed Angular Correlations (TDPAC) experimental results and FP-LAPW calculations enabled us the determination of lattice relaxations induced by the presence of the impurity and the charge state of an impurity donor level located in the band gap of the m-HfO2 semiconductor.