Vacuum ultraviolet reflectivity and band structure of SrTiO3 and BaTiO3

Bäuerle, D.; Braun, W.; Saile, V.; Sprüssel, G.; Koch, E. E.

doi:10.1007/bf01321179

Cited by 94 publications

(47 citation statements)

References 18 publications

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“…105 This observation also holds for the data of Cardona 101 and Baurerle et al. 106 Both the experimental and our calculated results show that the direct optical gap is larger than the smallest indirect band gap. Figure 6(c) shows the optical conductivity σ (ω) of SrTiO 3 .…”

Section: Optical Propertiessupporting

confidence: 90%

First principle electronic, structural, elastic, and optical properties of strontium titanate

et al. 2012

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We report self-consistent ab-initio electronic, structural, elastic, and optical properties of cubic SrTiO3 perovskite. Our non-relativistic calculations employed a generalized gradient approximation (GGA) potential and the linear combination of atomic orbitals (LCAO) formalism. The distinctive feature of our computations stem from solving self-consistently the system of equations describing the GGA, using the Bagayoko-Zhao-Williams (BZW) method. Our results are in agreement with experimental ones where the later are available. In particular, our theoretical, indirect band gap of 3.24 eV, at the experimental lattice constant of 3.91 Å, is in excellent agreement with experiment. Our predicted, equilibrium lattice constant is 3.92 Å, with a corresponding indirect band gap of 3.21 eV and bulk modulus of 183 GPa

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Section: Optical Propertiessupporting

confidence: 90%

First principle electronic, structural, elastic, and optical properties of strontium titanate

et al. 2012

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“…At energies of 16.5 eV and 20.1 eV, the features E 1 and E 2 of interband transitions show up clearly the Sr 4p → Ti 3d t 2g and e g excitations in ⌺5 boundary while only shoulder-like shapes of the two excitations are seen in n⌺13 boundary. Due to the experimental energy resolution, a spin-orbit splitting of the Sr 4p level by 0.6 eV, 60 i.e., splitting within E 1 and E 2 , is not observed in our VEELS measurements. For final states with energies higher than about 15 eV above the Fermi energy, the density of states shows a wealth of different overlapping energy levels that result in broad energy bands.…”

Section: A Electronic Structurementioning

confidence: 63%

Graded interface models for more accurate determination of van der Waals–London dispersion interactions across grain boundaries

et al. 2006

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Attractive van der Waals-London dispersion interactions between two half crystals arise from local physical property gradients within the interface layer separating the crystals. Hamaker coefficients and London dispersion energies were quantitatively determined for Σ5 and near-Σ13 grain boundaries in SrTiO 3 by analysis of spatially resolved valence electron energy-loss spectroscopy (VEELS) data. From the experimental data, local complex dielectric functions were determined, from which optical properties can be locally analyzed. Both local electronic structures and optical properties revealed gradients within the grain boundary cores of both investigated interfaces. The results show that even in the presence of atomically structured grain boundary cores with widths of less than 1 nm, optical properties have to be represented with gradual changes across the grain boundary structures to quantitatively reproduce accurate van der Waals-London dispersion interactions. London dispersion energies of the order of 10% of the apparent interface energies of SrTiO 3 were observed, demonstrating their significance in the grain boundary formation process. The application of different models to represent optical property gradients shows that long-range van der Waals-London dispersion interactions scale significantly with local, i.e., atomic length scale property variations. Attractive van der Waals-London dispersion interactions between two half crystals arise from local physical property gradients within the interface layer separating the crystals. Hamaker coefficients and London dispersion energies were quantitatively determined for ⌺5 and near-͚13 grain boundaries in SrTiO 3 by analysis of spatially resolved valence electron energy-loss spectroscopy ͑VEELS͒ data. From the experimental data, local complex dielectric functions were determined, from which optical properties can be locally analyzed. Both local electronic structures and optical properties revealed gradients within the grain boundary cores of both investigated interfaces. The results show that even in the presence of atomically structured grain boundary cores with widths of less than 1 nm, optical properties have to be represented with gradual changes across the grain boundary structures to quantitatively reproduce accurate van der Waals-London dispersion interactions. London dispersion energies of the order of 10% of the apparent interface energies of SrTiO 3 were observed, demonstrating their significance in the grain boundary formation process. The application of different models to represent optical property gradients shows that long-range van der Waals-London dispersion interactions scale significantly with local, i.e., atomic length scale property variations. Disciplines Engineering | Materials Science and Engineering Comments

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Section: Optical Propertiesmentioning

confidence: 99%

“…[9][10][11] In particular, the optical adsorption spectra were deduced from reflectivity measurements by Kramers-Kronig analysis. 10,11 x y X R Despite the tetragonal distortion, the optical spectra of the two phases show similar features, which has been traced back to the small effect of tetragonality (10-150 meV) on the band structure. 10,17 Two main adsorption peaks at 4.8 eV (labeled with P 1 in this work) and around 10.5 eV (P 2 , with two side peaks P 2 and P 2 at around 8.2 and 11.7 eV) dominate the spectrum.…”

Section: Optical Propertiesmentioning

confidence: 99%

“…The technological relevance is due to the still growing employment of BT for various technical applications in fields such as electronics, electromechanical energy conversion, nonlinear optics, and nonvolatile data storage. 6 Previous experimental and theoretical studies have focused on the structural, elastic, thermal, 1,2,7,8 electronic, [9][10][11] optical, 9,10 and vibrational 12,13 properties of the different phases. Furthermore, electron-spin resonance 14 as well as X-ray diffractometry 15 have been used to determine the dominant intrinsic defects in BT bulk and the structural properties of BaTiO 3 nanocrystalline powders.…”

Section: Introductionmentioning

confidence: 99%

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Barium titanate ground- and excited-state properties from first-principles calculations

et al. 2011

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We present a comprehensive theoretical investigation of paraelectric (cubic) and ferroelectric (tetragonal) BaTiO3. The atomic and electronic structure, piezoelectric tensor, Debye temperature, zone center phonon frequencies, and optical absorption are calculated for both phases from first principles. The structural and vibrational properties predicted from density functional theory are in good agreement with experiment and earlier theoretical work. The electronic structure and optical response are found to be very sensitive to quasiparticle and electron-hole attraction effects, which are accounted for by using the GW approach and by solving the Bethe-Salpeter equation, respectively. Electronic self-energy effects are found to open the band gap substantially, to 3.7 and 3.9 eV for the cubic and tetragonal phases, respectively. In contrast to earlier calculations, good agreement with the measured optical data is achieved. The ab initio thermodynamics predicts that the ferroelectric ordering will disappear at 419 K. It is shown that the phase transition is driven by the vibrational entropy of a variety of modes

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Vacuum ultraviolet reflectivity and band structure of SrTiO3 and BaTiO3

Cited by 94 publications

References 18 publications

First principle electronic, structural, elastic, and optical properties of strontium titanate

First principle electronic, structural, elastic, and optical properties of strontium titanate

Graded interface models for more accurate determination of van der Waals–London dispersion interactions across grain boundaries

Barium titanate ground- and excited-state properties from first-principles calculations

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