Orientation‐dependent surface composition of <i>i</i>n situ annealed strontium titanate

Zagonel, Luiz Fernando; Barrett, N.; Renault, O.; Bailly, Aude; Bäurer, Michael; Hoffmann, Michael J.; Shih, Shao‐Ju; Cockayne, D. J. H.

doi:10.1002/sia.2886

Cited by 24 publications

(25 citation statements)

References 21 publications

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“…It is possible that the surface termination in Ti‐rich material is different from Sr‐rich material, hindering diffusion into the contact areas. The surface termination of the particles can rearrange at temperatures as low as 800°C 17 to form a more stable surface compared with the one resulting from the milling procedure. The enhanced neck formation in the low temperature regime for the Sr‐rich compositions indicates that Ti termination of the surfaces in the Ti‐rich materials inhibits the diffusion to the contact areas (Fig.…”

Section: Discussionmentioning

confidence: 99%

Influence of Sr/Ti Stoichiometry on the Densification Behavior of Strontium Titanate

Bäurer

Kungl

Hoffmann

2009

Journal of the American Ceramic Society

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In order to control the preparation of strontium titanate with a well‐defined Sr/Ti stoichiometry produced by the mixed oxide route, dilatometric experiments have been conducted for compositions with Sr/Ti ratios ranging from 0.996 to 1.005. A significant change in sintering behavior has been detected going from a titania rich to a strontia rich composition. Combining observations of the microstructural evolution during different stages of sintering with results on defect chemistry from the literature makes an assessment of the basic mechanisms of sintering possible. The influence of zirconia abrasion from milling balls has been identified to be equal to a titania excess of the same amount. By means of dilatometric measurements it is possible to evaluate the A/B ratio with accuracy higher than 0.2 mol% from the shrinkage curves, providing a highly sensitive tool for the analysis of the stoichiometry in SrTiO3.

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Section: Discussionmentioning

confidence: 99%

Influence of Sr/Ti Stoichiometry on the Densification Behavior of Strontium Titanate

Bäurer

Kungl

Hoffmann

2009

Journal of the American Ceramic Society

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“…Random charges may result from adsorption of contaminants and/or the presence of impurities that can generate surface charges which depend strongly on the method of preparation of the samples. Surface charge disorder may also originate from the variation of the local crystallographic axes of the exposed surface of a clean polycrystalline sample which induces a variation of the local surface potential [3,4,2]. The heterogeneous structure of the charge disorder on dielectric surfaces and thus its statistical properties can be determined directly from Kelvin force microscopy measurements [1].…”

Section: Introductionmentioning

confidence: 99%

Sample-to-sample torque fluctuations in a system of coaxial randomly charged surfaces

et al. 2012

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Abstract. Polarizable randomly charged dielectric objects have been recently shown to exhibit long-range lateral and normal interaction forces even when they are effectively net neutral. These forces stem from an interplay between the quenched statistics of random charges and the induced dielectric image charges. This type of interaction has recently been evoked to interpret measurements of Casimir forces in vacuo, where a precise analysis of such disorder-induced effects appears to be necessary. Here we consider the torque acting on a randomly charged dielectric surface (or a sphere) mounted on a central axle next to another randomly charged surface and show that although the resultant mean torque is zero, its sample-to-sample fluctuation exhibits a long-range behavior with the separation distance between the juxtaposed surfaces and that, in particular, its root-mean-square value scales with the total area of the surfaces. Therefore, the disorder-induced torque between two randomly charged surfaces is expected to be much more pronounced than the disorder-induced lateral force and may provide an effective way to determine possible disorder effects in experiments, in a manner that is independent of the usual normal force measurement.PACS. 05.40.-a Fluctuation phenomena, random processes, noise, and Brownian motion -34.20.Gj Intermolecular and atom-molecule potentials and forces -03.50.De Classical electromagnetism

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“…The values were shifted by 0.98 eV compensating for the Schottky effect. 36 The dispersion relationship for the top valence band structure centered on the Γ point (k // = 0 Å −1 ) was obtained by first averaging the E bin vs. k slices of the k-PEEM image stack along the three equivalent MGM′ directions. Then, each constant-k intensity curve was fitted with a Gaussian peak yielding a peak position which was used to trace the dispersion relationship in the range of the inverted structure (E B = 0.86-0.91 eV; k // = 0-0.15 Å…”

Section: Photoemission Electron Momentum Microscopymentioning

confidence: 99%

Large-grain MBE-grown GaSe on GaAs with a Mexican hat-like valence band dispersion

et al. 2018

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Atomically thin GaSe has been predicted to have a non-parabolic, Mexican hat-like valence band structure due to the shift of the valence band maximum (VBM) near the Γ point which is expected to give rise to novel, unique properties such as tunable magnetism, high effective mass suppressing direct tunneling in scaled transistors, and an improved thermoelectric figure of merit. However, the synthesis of atomically thin GaSe remains challenging. Here, we report on the growth of atomically thin GaSe by molecular beam epitaxy (MBE) and demonstrate the high quality of the resulting van der Waals epitaxial films. The full valence band structure of nominal bilayer GaSe is revealed by photoemission electron momentum microscopy (k-PEEM), confirming the presence of a distorted valence band near the Γ point. Our results open the way to demonstrating interesting new physical phenomena based on MBE-grown GaSe films and atomically thin monochalcogenides in general.

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Orientation‐dependent surface composition of in situ annealed strontium titanate

Cited by 24 publications

References 21 publications

Influence of Sr/Ti Stoichiometry on the Densification Behavior of Strontium Titanate

Influence of Sr/Ti Stoichiometry on the Densification Behavior of Strontium Titanate

Sample-to-sample torque fluctuations in a system of coaxial randomly charged surfaces

Large-grain MBE-grown GaSe on GaAs with a Mexican hat-like valence band dispersion

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