INVESTIGADORES
ERRICO Leonardo Antonio
congresos y reuniones científicas
Título:
Experimental and ab initio study of the EFG at donor impurities in the Cr2O3:Ta semiconductor
Autor/es:
G. N. DARRIBA; L. A. ERRICO; E. MUÑOZ; D. RICHARD; P. D. EVERSHEIM; M. RENTERÍA
Lugar:
Buenos Aires
Reunión:
Workshop; Workshop "At the Frontiers of Condensed Matter physics IV"; 2008
Institución organizadora:
Comite internacional
Resumen:
In this work we report Perturbed-Angular-
Correlation (PAC) experiments on 181Hf/181Taimplanted
corundum Cr2O3 policrystals determining the magnitude and symmetry of the Electric-Field
Gradient tensor (EFG). The measurements were carried
out at 333 K after each step of a series of thermal
annealings in air in the range 673{1273 K performed
in order to obtain the maximum substitution of the Hf
impurities at defect free Cr sites in the semiconductor
crystal structure.
These results are analyzed in terms of self-consistent
electronic structure FP-LAPW calculations in the dilute
(1:4) Cr2O3:Ta system using the WIEN2k code.
The calculations were carried out for diverse charge
states of the impurities and are compared whit PCM
calculations and with the EFG results coming from
the PAC experiments using both 111In/111Cd and
181Hf/181Ta traces in the isomorphous -Al2O3, -
Fe2O3 and Cr2O3 semiconductors.
This combined study enables the determination of
lattice relaxations induced by the presence of impurities
in the host and the charge state of the impurity
donor level (Ta 5d) introduced in the band gap of the
semiconductor.