Electric-Field Gradients at 181Ta impurities in Sc2O3 semiconductor

D. RICHARD, E.L. MUÑOZ, L.A. ERRICO, P.D. EVERSHEIM, AND M. RENTERÍA

Buenos Aires

Workshop; FCM2010, International Workshop "At the Frontiers of Condensed Matter Physics V"; 2010

CAC-CNEA

In this work we present a combined ab initio and experimental study of 181Ta-doped Sc2O3 semiconductor. An extrapolationto 0 K of the experimental electric-field gradient (EFG) results obtained by Perturbed Angular Correlations (PAC) asa function of temperature suggested a reinterpretation of the charge state of the impurity in this semiconductor.The experimental temperature dependence of the EFGs at 181Ta probes located at defect-free cation sites C and D of theSc2O3 structure was determined in the range 373 K - 1173 K.The theoretical calculations were performed at diluted Ta impurities located at both cationic sites, using the Full-PotentialAugmented PlaneWave plus Local Orbital (FP-APW+lo) method in the framework of the Density Functional Theory (DFT),with a impurity dilution of 1:32. The structural atomic relaxations and the EFGs were studied for dierent charge states ofthe cell in order to simulate different ionization states of the double donor Ta impurity (with a neutral cell, and removing 1or 2 electrons from the cell). These APW+lo results were found to be in excellent agreement with the experimental values.