Experimental and ab initio study of the nuclear quadrupole interaction of 181 Ta-probes in an α-Fe2O3 single crystal

Darriba, G. N.; Muñoz, E. L.; Eversheim, P.D.; Rentería, M.

doi:10.1007/s10751-010-0244-x

Cited by 2 publications

(1 citation statement)

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“…More recently, different first-principles methods have been used to study theoretically pure and doped In 2 O 3 . − The development of certain methods for electron-density calculation in solids in the framework of density functional theory (DFT) opened the possibility to study the EFG in pure and doped binary oxides, combining hyperfine techniques results and first-principles calculations. − This kind of calculations provides a realistic model for an accurate description of subtle details of the electronic structure also very close to the nucleus, and therefore of the EFG, which reproduces accurately the experimental value, and also provides information about the physics behind it and its origin. The goal of these experimental and theoretical approaches is to determine the arising physical properties that are induced by the presence of the impurities.…”

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confidence: 99%

Experimental and First-Principles Theoretical Study of Structural and Electronic Properties in Tantalum-Doped In₂O₃ Semiconductor: Finding a Definitive Hyperfine Interaction Assignment

et al. 2016

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In this work we present an experimental and theoretical study from first-principles of the structural, electronic, and hyperfine properties of Ta-doped In2O3 semiconductor. The ab initio electronic structure calculations in the Ta-diluted In2O3 system enabled to obtain the structural lattice distortions and the hyperfine parameters when the Ta atom is placed at each cationic site of the bixbyite crystal structure. To this purpose we used the full-potential augmented plane wave plus local orbital (FP-APW+lo) method, within the density functional theory. The obtained results indicate that the substitutional Ta probe-impurity produces strong changes on the local structure. In addition, we performed accurate time-differential perturbed γ–γ angular correlations (TDPAC) key experiments in 181Hf(→181Ta)-implanted In2O3 samples with high crystallinity, in order to obtain high quality measurements of the electric-field gradient tensor (EFG) that unraveled the controversy settled in the literature and overcome dissimilar interpretations of previously reported TDPAC experiments. The experiments were performed at room temperature in air, after each step of a series of thermal annealing treatments in air at increasing temperatures in order to remove radiation damage and locate the 181Hf probes at substitutional cationic sites. We succeeded to obtained two well-defined hyperfine interactions that were assigned to 181Ta probes located at the two defect-free inequivalent cationic sites of the In2O3 crystal structure. The EFG calculations are in excellent agreement with the results of these TDPAC measurements, and show that the largest component of the diagonalized EFG, V 33, at the Ta site has mainly p character. The accuracy of the experiments together with the reliable and precise ab initio results allowed a definitive determination of the EFG at both cationic sites in this system. Formation energy calculations of defects were needed to determine the charge state of the 181Ta impurity, which agrees with a semiconducting character for the In2O3:Ta doped system.

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Section: Introductionmentioning

confidence: 99%

Experimental and First-Principles Theoretical Study of Structural and Electronic Properties in Tantalum-Doped In₂O₃ Semiconductor: Finding a Definitive Hyperfine Interaction Assignment

et al. 2016

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Ab Initio Study of Structural, Electronic, and Hyperfine Properties of n-type SnO₂:Ta Semiconductor

Darriba¹,

Muñoz²,

Errico

et al. 2014

J. Phys. Chem. C

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A detailed theoretical first-principles study of structural, electronic, and hyperfine properties at Sn and Ta sites of undoped and Ta-doped rutile SnO 2 is presented, using the Full-Potential Augmented Plane Wave plus local orbitals (FP-APW+lo) method. In the Ta-doped systems, we performed calculations for two different charge states. The predicted electric-field-gradient (EFG) tensor, the key magnitude in this study, for both charge states of the impurity result to be almost equal and in good agreement with Time-Differential Perturbed γ−γ Angular Correlation (TDPAC) results in 181 Ta-doped SnO 2 thin films. This study enables at present to discuss the origin of the EFG and the role played by the structural anisotropic contractions introduced by the Ta atom and the impurity charge state on the hyperfine properties. To determine the correct charge state of the impurity, we performed energetic studies, predicting the metallic behavior of degenerate semiconductors, in agreement with resistivity experimental results obtained in samples with the same Ta dilution.

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Experimental and ab initio study of the nuclear quadrupole interaction of 181 Ta-probes in an α-Fe2O3 single crystal

Cited by 2 publications

References 23 publications

Experimental and First-Principles Theoretical Study of Structural and Electronic Properties in Tantalum-Doped In₂O₃ Semiconductor: Finding a Definitive Hyperfine Interaction Assignment

Experimental and First-Principles Theoretical Study of Structural and Electronic Properties in Tantalum-Doped In₂O₃ Semiconductor: Finding a Definitive Hyperfine Interaction Assignment

Ab Initio Study of Structural, Electronic, and Hyperfine Properties of n-type SnO₂:Ta Semiconductor

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Experimental and ab initio study of the nuclear quadrupole interaction of 181 Ta-probes in an α-Fe2O3 single crystal

Cited by 2 publications

References 23 publications

Experimental and First-Principles Theoretical Study of Structural and Electronic Properties in Tantalum-Doped In2O3 Semiconductor: Finding a Definitive Hyperfine Interaction Assignment

Experimental and First-Principles Theoretical Study of Structural and Electronic Properties in Tantalum-Doped In2O3 Semiconductor: Finding a Definitive Hyperfine Interaction Assignment

Ab Initio Study of Structural, Electronic, and Hyperfine Properties of n-type SnO2:Ta Semiconductor

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Experimental and First-Principles Theoretical Study of Structural and Electronic Properties in Tantalum-Doped In₂O₃ Semiconductor: Finding a Definitive Hyperfine Interaction Assignment

Experimental and First-Principles Theoretical Study of Structural and Electronic Properties in Tantalum-Doped In₂O₃ Semiconductor: Finding a Definitive Hyperfine Interaction Assignment

Ab Initio Study of Structural, Electronic, and Hyperfine Properties of n-type SnO₂:Ta Semiconductor