The role of metallic impurities in oxide semiconductors: first-principles calculations and PAC experiments

L. A. ERRICO; G. FABRICIUS; M. RENTERÍA

PHYSICA STATUS SOLIDI B-BASIC RESEARCH

WILEY-VCH Verlag GmbH & Co. KGaA

Lugar: Weinheim (Alemania); Año: 2004 vol. 241 p. 2394 - 2398

0370-1972

We report an ab-initio comparative study of the electric-field-gradient tensor (EFG) and structural relaxationsintroduced by acceptor (Cd) and donor (Ta) impurities when they replace cations in a series of binaryoxides: TiO2, SnO2, and In2O3. Calculations were performed with the Full-Potential Linearized-Augmented Plane Waves method that allows us to treat the electronic structure and the atomic relaxationsin a fully self-consistent way. We considered different charge states for each impurity and studied the dependenceon these charge states of the electronic properties and the structural relaxations. Our results arecompared with available data coming from PAC experiments and previous calculations, allowing us toobtain a new insight on the role that metal impurities play in oxide semiconductors. It is clear from our resultsthat simple models can not describe the measured EFGs at impurities in oxides even approximately.