Electric-field gradients at Ta impurities in Sc2O3 semiconductor

In this work we present an ab initio study of Ta-doped Sc2O3 semiconductor. Calculations were performed at dilute Ta impurities located at both cationic sites of the host structure, using the Augmented Plane Wave plus Local Orbitals (APW + lo) method. The structural atomic relaxations and the electric-field gradients (EFG) were studied for different charge states of the cell in order to simulate different ionization states of the double-donor Ta impurity. From the results for the EFG tensor at Ta impurity sites and the comparison with experimental results obtained using the Time-Differential gamma-gamma Perturbed-Angular-Correlations technique we could determined the structural distortions induced by the Ta impurity and the electronic structure of the doped-semiconductor. (C) 2011 Elsevier B.V. All rights reserved.