Zhang-Rice physics and anomalous copper states in A-site ordered perovskites

Meyers, D.; Mukherjee, Swarnakamal; Cheng, Jinguang; Middey, S.; Zhou, Jianshi; Goodenough, John B; Gray, Barbara; Freeland, J. W.; Saha-Dasgupta, T.; Chakhalian, J.

doi:10.1038/srep01834

Cited by 51 publications

(43 citation statements)

References 44 publications

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“…While the valence of Cu remains 2 + (3 d 9 ) with hole doping, there is a clear emergence of a ligand hole state (3 d 9 L ) on the oxygen site, which is important for Cooper pairing4243. Detailed examination of the bulk cuprates have shown that this peak on both the Cu L -edge and O K -edge track directly with doping of the CuO 2 plane4445, which can be altered in the bulk by changing oxygen stoichiometry31, replacing Y with Ca4647, or doping at Cu sites48.…”

Section: Resultsmentioning

confidence: 99%

Superconductor to Mott insulator transition in YBa2Cu3O7/LaCaMnO3 heterostructures

Gray

Middey

Conti

et al. 2016

Sci Rep

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The superconductor-to-insulator transition (SIT) induced by means such as external magnetic fields, disorder or spatial confinement is a vivid illustration of a quantum phase transition dramatically affecting the superconducting order parameter. In pursuit of a new realization of the SIT by interfacial charge transfer, we developed extremely thin superlattices composed of high Tc superconductor YBa2Cu3O7 (YBCO) and colossal magnetoresistance ferromagnet La0.67Ca0.33MnO3 (LCMO). By using linearly polarized resonant X-ray absorption spectroscopy and magnetic circular dichroism, combined with hard X-ray photoelectron spectroscopy, we derived a complete picture of the interfacial carrier doping in cuprate and manganite atomic layers, leading to the transition from superconducting to an unusual Mott insulating state emerging with the increase of LCMO layer thickness. In addition, contrary to the common perception that only transition metal ions may respond to the charge transfer process, we found that charge is also actively compensated by rare-earth and alkaline-earth metal ions of the interface. Such deterministic control of Tc by pure electronic doping without any hindering effects of chemical substitution is another promising route to disentangle the role of disorder on the pseudo-gap and charge density wave phases of underdoped cuprates.

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Section: Resultsmentioning

confidence: 99%

Superconductor to Mott insulator transition in YBa2Cu3O7/LaCaMnO3 heterostructures

Gray

Middey

Conti

et al. 2016

Sci Rep

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“…The PFY-XA spectrum exhibits, as expected, two pronounced peaks representing the Cr L 3 and L 2 edges. 28,29 The TEY-XA spectrum that was recorded simultaneously as the PFY-XA spectrum, on the other hand, presents a flat line with no distinguishable Cr features, suggesting that the embedded species is not detectable by the TEY method. The TEY investigation of a standalone membrane by measuring sample drain current, as shown in the lower panel of figure 3, further corroborates this conclusion.…”

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confidence: 99%

Introducing Ionic-Current Detection for X-ray Absorption Spectroscopy in Liquid Cells

Schön

Xiao

Golnak

et al. 2017

J. Phys. Chem. Lett.

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Photons and electrons are two common relaxation products upon X-ray absorption, enabling fluorescence yield and electron yield detections for X-ray absorption spectroscopy (XAS).The ions that are created during the electron yield process are relaxation products too, which are exploited in this study to produce ion yield for XA detection. The ionic currents measured in a liquid cell filled with water or iron(III) nitrate aqueous solutions exhibit characteristic O K-edge and Fe L-edge absorption profiles as a function of excitation energy. Application of two electrodes installed in the cell is crucial for obtaining the XA spectra of the liquids behind membranes. Using a single electrode can only probe the species adsorbed on the membrane surface. The ionic-current detection, termed as total ion yield (TIY) in this study, also produces an undistorted Fe L-edge XA spectrum, indicating its promising role as a novel detection method for XAS studies in liquid cells.Key words: total ion yield (TIY), ionic current, liquid flow-cell, total electron yield (TEY), X-ray absorption spectroscopy (XAS) TOC GraphicPage 2 of 17 ACS Paragon Plus EnvironmentThe Journal of Physical Chemistry Letters 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 3 Studying the electronic structure of liquid water and aqueous solutions by soft X-rays has attracted much attention in recent years, 1-6 and continues to be a vital research field. Resonant excitation by X-rays is highly element-specific, which makes X-ray absorption spectroscopy (XAS) a widely used tool in many scientific disciplines. Due to the vacuum requirement for soft X-ray propagation, detection of XA spectra for liquid (volatile) samples in vacuum is very challenging. One of the most applied techniques to introduce liquid samples into a vacuum chamber is a liquid flow-cell with an ultra-thin membrane separating the liquid from the vacuum. 7,8 When equipped with multiple electrodes, such a liquid cell can act as a standard electrochemical cell. It is therefore of great interest to combine XAS and the liquid cell technique for in situ/operando investigations on liquid-based materials. [9][10][11][12] When a sample's thickness exceeds the penetration depth of soft X-rays, which is the case for the liquid cell adopted in this study, detection of XA spectra in the transmission mode is not applicable. Therefore, fluorescence yield (FY) or electron yield (EY) must be employed to acquire XA spectra. Due to the significant thickness of typical membranes, e.g. Si 3 N 4 and SiC membranes (~ 100 nm), the electrons created within liquid solutions cannot penetrate the membrane and escape into vacuum. The FY was thus considered the only feasible way to probe the liquid-phase species behind membranes. However, EY has been recently realized in liquid cell studies, thanks to the newly developed graphene membra...

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“…Perovskite materials with a formula of ABO 3 , where the A cation is 12-fold coordinated and the B cation is 6-fold coordinated with the oxygen, have been interested in various applications such as catalysis, energy, environment and bioscience applications131415161718. Recently, noble methods for preparation of perovskite with unique architecture and morphology have emerged in the form of porous, scaffold, and egg-shell skeleton due to their high geometric surface area with large cavities, light weight and flexibility for mass and heat transfer1920212223.…”

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confidence: 99%

Hollow Fibers Networked with Perovskite Nanoparticles for H2 Production from Heavy Oil

Jeon

Park

et al. 2013

Sci Rep

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Design of catalytic materials has been highlighted to build ultraclean use of heavy oil including liquid-to-gas technology to directly convert heavy hydrocarbons into H2–rich gas fuels. If the H2 is produced from such heavy oil through high-active and durable catalysts in reforming process that is being constructed in hydrogen infrastructure, it will be addressed into renewable energy systems. Herein, the three different hollow fiber catalysts networked with perovskite nanoparticles, LaCr0.8Ru0.2O3, LaCr0.8Ru0.1Ni0.1O3, and LaCr0.8Ni0.2O3 were prepared by using activated carbon fiber as a sacrificial template for H2 production from heavy gas oil reforming. The most important findings were arrived at: (i) catalysts had hollow fibrous architectures with well-crystallized structures, (ii) hollow fibers had a high specific surface area with a particle size of ≈50 nm, and (iii) the Ru substituted ones showed high efficiency for H2 production with substantial durability under high concentrations of S, N, and aromatic compounds.

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Zhang-Rice physics and anomalous copper states in A-site ordered perovskites

Cited by 51 publications

References 44 publications

Superconductor to Mott insulator transition in YBa2Cu3O7/LaCaMnO3 heterostructures

Superconductor to Mott insulator transition in YBa2Cu3O7/LaCaMnO3 heterostructures

Introducing Ionic-Current Detection for X-ray Absorption Spectroscopy in Liquid Cells

Hollow Fibers Networked with Perovskite Nanoparticles for H2 Production from Heavy Oil

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