FP-LAPW study of Cd-doped SnO

ERRICO L. A.; BIBILONI A. G.; PETRILLI H. M.; RENTERÍA M.

La Plata

Workshop; HFILP2005, International Workshop “35th Anniversary of Hyperfine Interactions at La Plata”; 2005

Laboratorio de Espectroscopía Nuclear e Interacciones Hiperfinas, FCE, UNLP e IFLP (CONICET)

The study of the interaction of the atomic nucleus with extranuclear fields hasproven to be quite useful in many contexts. Nuclear resonance and spectroscopictechniques, such as Nuclear-Quadrupole Resonance (NQR), Nuclear MagneticResonance (NMR), Mössbauer spectroscopy (MS), and Time-Differential Perturbed-AngularCorrelations (PAC), have been extensively applied to study materials from thepoint of view of solid-state physics and chemistry in order to elucidate the microscopicenvironment and the nature of chemical bonding of constituent or impurity atoms(probes) in solids in a large variety of compounds.Besides MS, PAC is probably the most common hyperfine interaction methodusing radioactive nuclei [1]. By means of this technique, it is possible to measure, theelectric-field gradient (EFG) tensor at a precise lattice site. All the information that theEFG tensor can provide about the system under study could be obtained byconfrontation of the experiment with an accurate prediction of the EFG, such as abinitio ones. Since the EFG is very sensitive to the anisotropic charge distribution closeto the probe-nucleus, for its accurate calculation the entire electronic configuration ofthe host, perturbed by the presence of the impurity, has to be determined. In this sense,in 1999 we began a systematic study, in the framework of the Density FunctionalTheroy (DFT), of electronic and structural properties at impurities in oxides, startingwith Cd in TiO2 and SnO2 [2-4].In this work we report a DFT study, using the Full-Potential Linearized-AugmentedPlane Waves method, of the EFG at Cd impurities located at the cation site in thesemiconductor SnO. In order to simulate the diluted Cd-impurity in the SnO host and tocalculate the electronic structure of the system we used the supercell approach, studyingthe relaxation introduced by the impurity in the lattice. Our prediction for the EFGtensor are compared to experimental PAC results [5], to point-charge model predictionsand to results obtained with the PAW method.[1] See, e.g., E.N. Kaufmann and R.J. Vianden, Rev.Mod.Phys. 51, 161 (1979).[2] L.A. Errico, G. Fabricius, M. Rentería, P. de la Presa, and M. Forker, Phys.Rev.Lett.89, 55503 (2002).[3] L.A. Errico, G. Fabricius, and M. Rentería, Phys.Rev. B 67, 144104 (2003).[4] L.A. Errico, G. Fabricius, and M. Rentería, Hyperfine Interact. 136/137, 749 (2001).[5] M.Rentería, A.G. Bibiloni, M.S. Moreno, J. Desimoni, R.C. Mercader, A. Bartos,M. Uhrmacher, and K.P. Lieb, J.Phys. - Cond. Matt. 3, 3625 (1991).Keywords: SnO, Cd impurity, relaxations, FP-LAPW, ab initio, DFT, EFG, PAC,oxide , PAW