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Electric-field gradients at Ta donor impurities in Cr2O3(Ta) semiconductor |
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| Authors: | GN Darriba LA Errico EL Muoz D Richard PD Eversheim M Rentería |
| Institution: | aDepartamento de Física and IFLP (CONICET-UNLP), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CC 67, 1900 La Plata, Argentina;bUniversidad Nacional del Noroeste Bonaerense (UNNOBA), Monteagudo 2772, 2700 Pergamino, Argentina;cHelmholtz-Institut für Strahlen-und Kernphysik (H-ISKP), Universität Bonn, Nussallee 14–16, 53115 Bonn, Germany |
| Abstract: | We report perturbed-angular-correlation (PAC) experiments on 181Hf(→181Ta)-implanted corundum Cr2O3 powder samples in order to determine the magnitude and symmetry of the electric-field gradient (EFG) tensor at Ta donor impurity sites of this semiconductor. These results are analyzed in the framework of ab initio full-potential augmented-plane wave plus local orbitals (FP−APW+lo) calculations. The results are also compared with EFG results coming from PAC experiments in isomorphous α-Al2O3 and α-Fe2O3 doped with 111In→111Cd and 181Hf→181Ta tracers. This combined analysis enables us to quantify the magnitude of the lattice relaxations induced by the presence of the impurity and to determine the charge state of the impurity donor level introduced by Ta in the band gap of the semiconductor. |
| Keywords: | Cr2O3 PAC Ab initio calculations Electric-field gradient |
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