Experimental and ab initio study of the EFG at donor impurities in the Cr2O3:Ta semiconductor

G. N. DARRIBA; E. L. MUÑOZ; L. A. ERRICO; D. RICHARD; P. D. EVERSHEIM; M. RENTERÍA

San Martín, Buenos Aires, Argentina

Workshop; At the Frontiers of Condensed Matter IV 2008; 2008

In this work we report Perturbed-Angular-Correlation (PAC) experiments on 181Hf/181Ta-implanted corundum Cr2O3 policrystals determining the magnitude and symmetry of the EFG. The measurements was carried out at room temperature, after the different in order to finding the annealing for which obtained the major number of probes located in the substitutional cation sites and free of defects of the semiconductor. These results are analyzed in terms of self-consistent electronic structure FP-LAPW calculations in the dilute (1:4) Cr2O3:Ta system with the WIEN2k implementation. The calculations was carried out for diverse charge states of the impurities, compared whit PCM calculations, and compared with EFG results coming from PAC experiments using 111In/111Cd tracers and for both probes (181Ta and 111Cd) in isomorphous polycrystalline a-Al2O3 and a-Fe2O3.