Atomic and electronic structure probed by X-ray absorption spectroscopy: Full multiple scattering analysis with the G4XANES package

Longa, S. Della; Soldatov, A. V.; Pompa, M.; Bianconi, A.

doi:10.1016/0927-0256(95)00027-n

Cited by 56 publications

(12 citation statements)

References 43 publications

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“…In agreement with the prediction [1], polarons have been detected in cuprates [13][14][15], using X-ray absorption spectroscopy [16,17] and confirmed by theories [18,19]. However, experiments show two unexpected features.…”

Section: Introductionsupporting

confidence: 78%

The Road Map toward Room-Temperature Superconductivity: Manipulating Different Pairing Channels in Systems Composed of Multiple Electronic Components

et al. 2017

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Abstract:While it is known that the amplification of the superconducting critical temperature T C is possible in a system of multiple electronic components in comparison with a single component system, many different road maps for room temperature superconductivity have been proposed for a variety of multicomponent scenarios. Here we focus on the scenario where the first electronic component is assumed to have a vanishing Fermi velocity corresponding to a case of the intermediate polaronic regime, and the second electronic component is in the weak coupling regime with standard high Fermi velocity using a mean field theory for multiband superconductivity. This roadmap is motivated by compelling experimental evidence for one component in the proximity of a Lifshitz transition in cuprates, diborides, and iron based superconductors. By keeping a constant and small exchange interaction between the two electron fluids, we search for the optimum coupling strength in the electronic polaronic component which gives the largest amplification of the superconducting critical temperature in comparison with the case of a single electronic component.

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Section: Introductionsupporting

confidence: 78%

The Road Map toward Room-Temperature Superconductivity: Manipulating Different Pairing Channels in Systems Composed of Multiple Electronic Components

et al. 2017

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“…X-ray diffraction (XRD) can help to understand the different structures. Experiments using XANES (X-ray absorption near edge structure) spectroscopy will elucidate the evolution and influence of the local geometry of the tungsten atoms [34][35][36][37][38].…”

Section: The System Beryllium-oxygen-tungstenmentioning

confidence: 99%

Comparative Study of the Reactivity of the Tungsten Oxides WO2 and WO3 with Beryllium at Temperatures up to 1273 K

Köppen¹

2019

Condensed Matter

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Tungsten oxides play a pivotal role in a variety of modern technologies, e.g., switchable glasses, wastewater treatment, and modern gas sensors. Metallic tungsten is used as armor material, for example in gas turbines as well as future fusion power devices. In the first case, oxides are desired as functional materials; while in the second case, oxides can lead to catastrophic failures, so avoiding the oxidation of tungsten is desired. In both cases, it is crucial to understand the reactivity of tungsten oxides with other chemicals. In this study, the different reactivities of tungsten oxides with the highly-oxophilic beryllium are studied and compared. Tungsten-(IV)-oxide and tungsten-(VI)-oxide layers are prepared on a tungsten substrate. In the next step, a thin film of beryllium is evaporated on the samples. In consecutive steps, the sample is heated in steps of 100 K from room temperature (r. t.) to 1273 K. The chemical composition is investigated after each experimental step by high-resolution X-ray photoelectron spectroscopy (XPS) for all involved core levels as well as the valence band. A model is developed to analyze the chemical reactions after each step. In this study, we find that tungsten trioxide was already reduced by beryllium at r. t. and started to react to form the ternary compounds BeWO3 and BeWO4 at temperatures starting from 673 K. However, tungsten dioxide is resistant to reduction at temperatures of up to 1173 K. In conclusion, we find WO2 to be much more chemically resistant to the reduction agent Be than WO3.

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“…In the formation of the superconducting condensates [13][14][15] The spatial complexity emerges in these systems since by tuning the chemical potential near a Lifshitz transition the electronic system made by strongly interacting particles is predicted to undergo phase separation [25,26] which can be frustrated by a long range Coulomb interaction giving a multiscale phase separation going from the nanoscale to the micron scale spanning the mesoscale spatial range between the atomic and macroscopic space. In fact phase separation has been observed in cuprates and related materials [27][28][29][30][31][32] and it has been related with exotic theories of high temperature superconductivity [33][34][35][36][37][38][39][40][41][42][43] The complex electronic and structural landscape of the strongly correlated electronic structure of the quasi 2D copper oxide plane in cuprate superconductors, was first unveiled by XANES spectroscopy using synchrotron radiation [44][45][46][47][48]. It has provided first, the evidence of the orbital character of the itinerant holes (in the oxygen 2p orbital) [49] and second, the coexistence of two electronic states at the Fermi level: polarons [50] (where the ratio between the pairing interaction and the local Fermi energy is close to one) around the antinodal point and free quasi-particles around the nodal point of the Brillouin zone.…”

mentioning

confidence: 99%

Complex Lattice and Charge Inhomogeneity Favoring Quantum Coherence in High-Temperature Superconductors

Bianconi

2016

J Supercond Nov Magn

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The presence of two components in the electron fluid of high temperature superconductors and the complex charge and lattice inhomogeneity have been the hot topics of the international conference of the superstripes series, Superstripes 2015, held in Ischia in 2015. The debate on the mechanisms for reaching room temperature superconductors has been boosted by the discovery of superconductivity with the highest critical temperature in pressurized sulfur hydride. Different complex electronic and structural landscapes showing up in superconductors, which resist to the decoherence effects of high temperature, have been discussed. While low temperature superconductors described by the BCS approximation are made of a single condensate in the weak coupling the high temperature superconductors are made of coexisting multiple condensates (in different spots of the k--space and the real space) some in the BCS--BEC crossover regime and others in the BCS regime. The role of "shape resonance" in the exchange interaction between these different condensates, like "the Fano--Feshbach resonance" in ultracold gasses, is emerging as a key term for high temperature superconductivity.

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Atomic and electronic structure probed by X-ray absorption spectroscopy: Full multiple scattering analysis with the G4XANES package

Cited by 56 publications

References 43 publications

The Road Map toward Room-Temperature Superconductivity: Manipulating Different Pairing Channels in Systems Composed of Multiple Electronic Components

The Road Map toward Room-Temperature Superconductivity: Manipulating Different Pairing Channels in Systems Composed of Multiple Electronic Components

Comparative Study of the Reactivity of the Tungsten Oxides WO2 and WO3 with Beryllium at Temperatures up to 1273 K

Complex Lattice and Charge Inhomogeneity Favoring Quantum Coherence in High-Temperature Superconductors

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