INVESTIGADORES
ERRICO Leonardo Antonio
congresos y reuniones científicas
Título:
Ab initio study of the electric-field gradient at Cd-doped SnO
Autor/es:
L. A. ERRICO.; M. RENTERÍA; H. M. PETRILLI
Lugar:
Foz Do Iguazu, Brasil
Reunión:
Conferencia; XIV International Conference on Hyperfine Interactions & XVIII International Symposium on Nuclear Quadrupole Interaction; 2007
Institución organizadora:
UNLP - USP
Resumen:
Hyperfine techniques, and in particular  Time-Differential Perturbed-Angular-Correlation (TDPAC) spectroscopy,have been increasingly applied to condensed-matter problems through the precise characterization of theelectric-field-gradient (EFG) tensor at diluted (ppm) radioactive probe atoms, adequately introduced at substitutionalhost lattice sites. The single-atom counting of this technique, in combination with its highly localized sensitivity (duethe r−3 dependence of the electric-quadrupole interaction), allows a detailed investigation of both structural andelectronic properties of the systems under study. Generally, the probe is an impurity dopant in the host. For thisreason, interpreting TDPAC experimental results involves the understanding of the chemical differences between theimpurity probe atom and the indigenous ion replaced by the impurity. For an accurate calculation of the structuraland electronic properties of the doped system, the electronic configuration of the host, perturbed by the presence of the impurity, has to be determined what requires the use of a state-of-the-art ab initio electronic structure calculation. In this work we report a Density Functional Theory (DFT) study of the EFG at Ta impurities located at the cation site in the semiconductor SnO using the Full-Potential Linearized-Augmented Plane Waves (FPLAPW)method. The predictions for the EFG tensor are compared with available experimental TDPAC results and withrecent DFT calculations performed for Cd-doped SnO. In this way we can compare the electronic structure and the structural relaxations introduced by acceptor (Cd) and donor (Ta) impurities when they replace cations in SnO. We consider different charge states for the impurity and study the dependence of the electronic properties and structural relaxations on these charged states. Our combined experimental-ab initio approach adds to the systematic study of the role played by metal impurities in semiconductor oxides which we have been performing.