Photoelectron spectroscopic study of the valence and core-level electronic structure of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">BaTiO</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>

Hudson, Lawrence T.; Kurtz, Richard L.; Robey, S. W.; Temple, D.; Stockbauer, Roger

doi:10.1103/physrevb.47.1174

Cited by 130 publications

(51 citation statements)

References 31 publications

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“…Also, the LDA calculations revealed that, despite the mainly ionic character of BaTiO 3 , some p-d hybridization is present, 13 and the sensitivity of this hybridization to off-center atomic displacements is a fundamental force driving the system to the ferroelectric state. 7,13 Despite these successes, the comparison between the LDA band-structure energies and the photoemission spectra 33 show typical discrepancies that are worthy of investigation.…”

Section: B Batio3 and Getementioning

confidence: 99%

Strong-correlation effects in Born effective charges

Filippetti

Spaldin

2003

Phys. Rev. B

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Large values of Born effective charges are generally considered as reliable indicators of the genuine tendency of an insulator towards ferroelectric instability. However, these quantities can be very much influenced by strong electron correlation and metallic behavior, which are not exclusive properties of ferroelectric materials. In this paper we compare the Born effective charges of some prototypical ferroelectrics with those of magnetic, non-ferroelectric compounds using a novel, self-interaction free methodology that improves on the local-density approximation description of the electronic properties. We show that the inclusion of strong-correlation effects systermatically reduces the size of the Born effective charges and the electron localization lengths. Furthermore we give an interpretation of the Born effective charges in terms of band energy structure and orbital occupations which can be used as a guideline to rationalize their values in the general case.

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Section: B Batio3 and Getementioning

confidence: 99%

Strong-correlation effects in Born effective charges

Filippetti

Spaldin

2003

Phys. Rev. B

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“…Los materiales llamados perovskitas que tienen un composición química AMO 3 , comprenden a un número apreciable de compuestos. Estos óxidos tienen una diversidad de propiedades mecánicas, eléctricas, magnéticas y ópticas que son de importancia estudiar tanto desde le punto de vista básico como aplicado.…”

Section: Introductionunclassified

“…Desde el punto de vista de la estructura electrónica hay una distinta hibridación entre los orbitales p(Sr) y los p(O) comparada con la producida por los p(Ba) y los p(O) y por este motivo los orbitales electrónicos cambian conforme cambia la composición. [3] En términos macróscopicos de las distancias A-O y los radios iónicos r A , el reemplazo de Sr por Ba produciría un estado de equilibrio donde hay compensación entre la atracción Sr-O y la del Ba-O. Entonces la separación de equilibrio será intermedia entre los valores correspondientes a los compuestos puros.…”

Section: Introductionunclassified

La temperatura de transición en SrxBa1-xHfO3

Alonso¹,

Horowitz²,

García³

2002

Bol. Soc. Esp. Ceram. Vidr.

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En este trabajo se presenta las temperaturas de transición T C a la estructura cúbica, en la familia de compuestos Sr X Ba 1-X HfO 3 donde x es igual a 0.12, 0.25, 0.50, 0.75 y 0.88, determinadas por medidas de la Correlación Angular Perturbada y usando al tantalio como sonda. El interés es estudiar como la sustitución de estroncio por bario modifica dicha temperatura. El BaHfO 3 es cúbico a temperatura ambiente. En cambio, el SrHfO 3 presenta una transición estructural de tetragonal a cúbica cuando T C1 ≈ 1400 K. Por debajo de esta temperatura y hasta T C2 ≈ 1000 K los octaedros de oxígeno están rotados uno con respecto al consecutivo, en un ángulo ϕ alrededor del eje z de la red tetragonal que disminuye a cero a medida que T→T C . Esta rotación está relacionada con la interacción del estroncio con el oxígeno, ya que el radio iónico del catión r Sr (≈ 1.13 Å) permite un mayor acercamiento entre ambos que el bario al oxígeno, pues r Ba (≈ 1.35 Å). Entonces, en los compuestos Sr X Ba 1-X HfO 3 se espera que haya una competencia entre la interacción Ba-O, separados por 2.9502 Å y la interacción Sr-O separados por una distancia menor, 2.9089 Å en las fases cúbicas de los respectivos compuestos puros. Palabras clave: Perovskitas, Transiciones de Fase, Interacciones Hiperfinas, Defectos.The transition temperature to the cubic phase in Sr x Ba 1-x HfO 3 .In this contribution the transition temperature T C to the cubic phase in Sr x Ba 1-x HfO 3 compounds with x = 0.12, 0.25, 0.50, 0.75 and 0.88 is presented. These temperatures were deduced from the measurements of the perturbed angular correlation on tantalum probes. The purpose of this work is to study how the Sr substitution by Ba affect this temperature. The oxides BaHfO 3 and SrHfO 3 have at RT cubic and orthorhombic structures, respectively. The Sr-compound transform from tetragonal to cubic at T C1 ≈ 1400. From T C2 ≈ 1000K and up to T C1 the oxygen octahedra are tilted and the tilt angle decreases steadily as T approaches T C1 . This rotation is originated by the interaction of strontium with oxygen because the Sr ionic radius (r Sr ≈ 1.13 Å) allows to be closer than Ba (r Ba ≈ 1.35 Å). Then in Sr x Ba 1-x HfO 3 compounds a competition between the Ba-O interaction, 2.9502 Å apart and Sr-O interaction at a distance of 2.9098 Å in their respective pure compounds, is established. INTRODUCCIÓNLos materiales llamados perovskitas que tienen un composición química AMO 3 , comprenden a un número apreciable de compuestos. Estos óxidos tienen una diversidad de propiedades mecánicas, eléctricas, magnéticas y ópticas que son de importancia estudiar tanto desde le punto de vista básico como aplicado. La estructura de estos compuestos es cúbica o cúbica distorsionada, donde los cationes A ocupan los vértices del cubo, los oxígenos están en el centro de las caras y el metal M en el centro del cuerpo. Los octaedros MO 6 forman una subred y los cationes A otra, interpenetradas entre sí. Desde el punto de vista de la estructura electrónica, hay dos tipos de interacción, una ent...

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“…In general, it has been found that single crystal BaTiO 3 can be chemically reduced by annealing in vacuum ͑T = 900-1200 K͒, as indicated by a progressive change in the sample color from light yellow to green, and eventually to blue and black. [22][23][24][25][26] The reduction in BaTiO 3 occurs through the loss of oxygen atoms, which makes the material n-type and pins the Fermi level near the bottom edge of the conduction band. 24 It has also been shown that surface oxygen vaa͒ Author to whom correspondence should be addressed; electronic mail: bonnell@lrsm.upenn.edu cancies can be generated by Ar-ion bombardment.…”

Section: Introductionmentioning

confidence: 99%

“…[22][23][24][25][26] The reduction in BaTiO 3 occurs through the loss of oxygen atoms, which makes the material n-type and pins the Fermi level near the bottom edge of the conduction band. 24 It has also been shown that surface oxygen vaa͒ Author to whom correspondence should be addressed; electronic mail: bonnell@lrsm.upenn.edu cancies can be generated by Ar-ion bombardment. 22,23 These defects can be detected by surface sensitive techniques such as photoelectron spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

Defect-mediated adsorption of methanol and carbon dioxide on BaTiO3(001)

Garra

Vohs

Bonnell

2009

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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The surface chemistry of single crystal barium titanate (BaTiO3) has been studied using temperature programmed desorption (TPD). TPD measurements were performed with several probe molecules, including methanol and carbon dioxide. The role of oxygen vacancies in the adsorption and reaction of these molecules was examined by annealing the crystal under oxidizing or reducing conditions prior to performing TPD. It is shown that the adsorption and reaction of methanol and carbon dioxide are enhanced on BaTiO3(001) by annealing the crystal under reducing conditions.

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Photoelectron spectroscopic study of the valence and core-level electronic structure ofBaTiO3

Cited by 130 publications

References 31 publications

Strong-correlation effects in Born effective charges

Strong-correlation effects in Born effective charges

La temperatura de transición en Sr<sub>x</sub>Ba<sub>1-x</sub>HfO<sub>3</sub>

Defect-mediated adsorption of methanol and carbon dioxide on BaTiO3(001)

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