Anomalous expansion of the copper-apical-oxygen distance in superconducting cuprate bilayers

Zhou, Hua; Yacoby, Y.; Butko, V. Yu.; Логвенов, Г.; Božović, I.; Pindak, R.

doi:10.1073/pnas.0914702107

Cited by 64 publications

(45 citation statements)

References 31 publications

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“…COBRA is a phase-retrieval algorithm that has been proven useful in the study of buried interfaces in epitaxial heterostructures. [24][25][26][27][28] The resulting electron density profiles and extracted integrated electron numbers for both the AO and BO 2 layers (where A = Sr or La and B = Ti or Al) along the out-of-plane direction, z, are shown in Figs. 2(c)-2(f) for the 9-and 24-unit-cell-thick LAO films.…”

Section: -10mentioning

confidence: 99%

Octahedral rotations in strained LaAlO3/SrTiO3 (001) heterostructures

Fister¹,

Zhou²,

Luo³

et al. 2014

APL Materials

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Many complex oxides display an array of structural instabilities often tied to altered electronic behavior. For oxide heterostructures, several different interfacial effects can dramatically change the nature of these instabilities. Here, we investigate LaAlO3/SrTiO3 (001) heterostructures using synchrotron x-ray scattering. We find that when cooling from high temperature, LaAlO3 transforms from the \documentclass[12pt]{minimal}\begin{document}$Pm\bar{3}m$\end{document}Pm3¯m to the Imma phase due to strain. Furthermore, the first 4 unit cells of the film adjacent to the substrate exhibit a gradient in rotation angle that can couple with polar displacements in films thinner than that necessary for 2D electron gas formation.

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Section: -10mentioning

confidence: 99%

Octahedral rotations in strained LaAlO3/SrTiO3 (001) heterostructures

Fister¹,

Zhou²,

Luo³

et al. 2014

APL Materials

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“…To overcome this, threedimensional reconstruction of oxide surface and sub-surface structures have been consistently demonstrated using Coherent Bragg Rod Analysis (COBRA) 262, 263 -a phase-retrieval method that combines information from multiple crystal truncation rods to determine the crystal structure near the surface. Such studies have been applied to understanding electrocatalysis in solid oxide fuel cell applications 232,264 and oxide electronics, 233,[265][266][267] and could greatly benefit the study of oxide surfaces for the ORR/OER in alkaline solutions. However, the low atomic number of oxygen results in weak scattering, making X-ray scattering techniques better suited for studying the catalyst surface structure rather than the adsorbate structure.…”

Section: In Situ Spectroscopic Approachesmentioning

confidence: 99%

Toward the rational design of non-precious transition metal oxides for oxygen electrocatalysis

Hong

Risch

Stoerzinger

et al. 2015

Energy Environ. Sci.

1,695

1,491

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REVIEWThis journal is © The Royal Society of Chemistry 2013 J. Name., 2013, 00, 1-3 | 1 In this Review, we discuss the state-of-the-art understanding of non-precious transition metal oxides that catalyze the oxygen reduction and evolution reactions. Understanding and mastering the kinetics of oxygen electrocatalysis is instrumental to making use of photosynthesis, advancing solar fuels, fuel cells, electrolyzers, and metal-air batteries. We first present key insights, assumptions and limitations of well-known activity descriptors and reaction mechanisms in the past four decades. The turnover frequency of crystalline oxides as promising catalysts is also put into perspective with amorphous oxides and photosystem II. Particular attention is paid to electronic structure parameters that can potentially govern the adsorbate binding strength and thus provide simple rationales and design principles to predict new catalyst chemistries with enhanced activity. We share new perspective synthesizing mechanism and electronic descriptors developed from both molecular orbital and solid state band structure principles. We conclude with an outlook on the opportunities in future research within this rapidly developing field. Broader ContextThe formation of chemical bonds is an energy dense mode of storing energy. In both nature and technology, the electrochemical generation and consumption of fuels is one of the most efficient routes for energy usage. Solar and electrical energy can be stored in chemical bonds by splitting water or metal oxides to produce hydrogen and metal. These compounds can then be oxidized to produce energy when coupled to the reduction of oxygen. However, these device efficiencies are severely limited by the catalysis of oxygen electrochemical processes -namely the oxygen reduction reaction and oxygen evolution reaction, which have slow kinetics. Non-precious transition metal oxides show promise as cost-effective substitutes for noble metals in commercially viable renewable energy storage and conversion devices. Furthermore, this class of materials has ben efitted from a wealth of spectroscopic and first-principles studies in the past few decades, providing the frameworks and theories needed to understand the electronic structure and design optimal catalysts. The incredibly diverse range of chemistries and physical properties that can be explored in oxide families afford numerous degrees of freedom for conducting systematic investigations relating intrinsic mat erial properties to catalytic performance. Here, we present background on the fundamental concepts in catalysis for the rational design of transition metal perovskite oxide catalysts for oxygen electrocatalysis and critically examine the current understanding a nd its impact on future directions of perovskite catalysts.

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“…For this, another novel synchrotron-based X-ray phaseretrieval technique was employed, coherent Bragg-rod analysis (COBRA) [9]. The measured diffraction intensities, and the fact that the complex structure factors vary continuously along the substrate-defined Bragg rods, are used to determine the diffraction phases and the complex structure factors.…”

Section: Interface Superconductivitymentioning

confidence: 99%

Insights from the study of high-temperature interface superconductivity

Pereiro

Bollinger

Логвенов

et al. 2012

Phil. Trans. R. Soc. A.

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A brief overview is given of the studies of high-temperature interface superconductivity based on atomic-layer-by-layer molecular beam epitaxy (ALL-MBE). A number of difficult materials science and physics questions have been tackled, frequently at the expense of some technical tour de force, and sometimes even by introducing new techniques. ALL-MBE is especially suitable to address questions related to surface and interface physics. Using this technique, it has been demonstrated that high-temperature superconductivity can occur in a single copper oxide layer-the thinnest superconductor known. It has been shown that interface superconductivity in cuprates is a genuine electronic effect-it arises from charge transfer (electron depletion and accumulation) across the interface driven by the difference in chemical potentials rather than from cation diffusion and mixing. We have also understood the nature of the superconductorinsulator phase transition as a function of doping. However, a few important questions, such as the mechanism of interfacial enhancement of the critical temperature, are still outstanding.

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Anomalous expansion of the copper-apical-oxygen distance in superconducting cuprate bilayers

Cited by 64 publications

References 31 publications

Octahedral rotations in strained LaAlO3/SrTiO3 (001) heterostructures

Octahedral rotations in strained LaAlO3/SrTiO3 (001) heterostructures

Toward the rational design of non-precious transition metal oxides for oxygen electrocatalysis

Insights from the study of high-temperature interface superconductivity

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