scholarly journals Core-Level X-Ray Spectroscopy of Infinite-Layer Nickelate: LDA+DMFT Study

2021 ◽  
Vol 11 (4) ◽  
Author(s):  
Keisuke Higashi ◽  
Mathias Winder ◽  
Jan Kuneš ◽  
Atsushi Hariki
Keyword(s):  
Core Level ◽  
X Ray ◽  
Infinite Layer

Nano-probe x-ray analysis and high-resolution imaging on planar defects in high-pressure synthesized infinite-layer superconductor

1994 ◽  
Vol 52 ◽  
pp. 728-729
Author(s):  
Y. Y. Wang ◽  
H. Zhang ◽  
V. P. Dravid ◽  
H. Zhang ◽  
L. D. Marks ◽  
...  
Keyword(s):  
High Pressure ◽  
High Resolution ◽  
Atomic Structure ◽  
Emission Spectra ◽  
High Resolution Electron Microscopy ◽  
Planar Defects ◽  
X Ray ◽  
Infinite Layer ◽  
Resolution Electron ◽  
Resolution Imaging

Azuma et al. observed planar defects in a high pressure synthesized infinitelayer compound (i.e. ACuO2 (A=cation)), which exhibits superconductivity at ~110 K. It was proposed that the defects are cation deficient and that the superconductivity in this material is related to the planar defects. In this report, we present quantitative analysis of the planar defects utilizing nanometer probe xray microanalysis, high resolution electron microscopy, and image simulation to determine the chemical composition and atomic structure of the planar defects. We propose an atomic structure model for the planar defects.Infinite-layer samples with the nominal chemical formula, (Sr1-xCax)yCuO2 (x=0.3; y=0.9,1.0,1.1), were prepared using solid state synthesized low pressure forms of (Sr1-xCax)CuO2 with additions of CuO or (Sr1-xCax)2CuO3, followed by a high pressure treatment.Quantitative x-ray microanalysis, with a 1 nm probe, was performed using a cold field emission gun TEM (Hitachi HF-2000) equipped with an Oxford Pentafet thin-window x-ray detector. The probe was positioned on the planar defects, which has a 0.74 nm width, and x-ray emission spectra from the defects were compared with those obtained from vicinity regions.

scholarly journals A method for studying pico to microsecond time-resolved core-level spectroscopy used to investigate electron dynamics in quantum dots

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Tamara Sloboda ◽  
Sebastian Svanström ◽  
Fredrik O. L. Johansson ◽  
Aneta Andruszkiewicz ◽  
Xiaoliang Zhang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Electron Injection ◽  
Core Level ◽  
Pump Laser ◽  
Repetition Frequency ◽  
Specific Information ◽  
Single Experiment ◽  
Time Resolved ◽  
X Ray ◽  
Pbs Quantum Dots

AbstractTime-resolved photoelectron spectroscopy can give insights into carrier dynamics and offers the possibility of element and site-specific information through the measurements of core levels. In this paper, we demonstrate that this method can access electrons dynamics in PbS quantum dots over a wide time window spanning from pico- to microseconds in a single experiment carried out at the synchrotron facility BESSY II. The method is sensitive to small changes in core level positions. Fast measurements at low pump fluences are enabled by the use of a pump laser at a lower repetition frequency than the repetition frequency of the X-ray pulses used to probe the core level electrons: Through the use of a time-resolved spectrometer, time-dependent analysis of data from all synchrotron pulses is possible. Furthermore, by picosecond control of the pump laser arrival at the sample relative to the X-ray pulses, a time-resolution limited only by the length of the X-ray pulses is achieved. Using this method, we studied the charge dynamics in thin film samples of PbS quantum dots on n-type MgZnO substrates through time-resolved measurements of the Pb 5d core level. We found a time-resolved core level shift, which we could assign to electron injection and charge accumulation at the MgZnO/PbS quantum dots interface. This assignment was confirmed through the measurement of PbS films with different thicknesses. Our results therefore give insight into the magnitude of the photovoltage generated specifically at the MgZnO/PbS interface and into the timescale of charge transport and electron injection, as well as into the timescale of charge recombination at this interface. It is a unique feature of our method that the timescale of both these processes can be accessed in a single experiment and investigated for a specific interface.

Asymptotic theory and core level x-ray photoemission spectra

1980 ◽  
Vol 22 (10) ◽  
pp. 4994-4996 ◽  
Author(s):  
L. A. Feldkamp ◽  
L. C. Davis
Keyword(s):  
Asymptotic Theory ◽  
Core Level ◽  
X Ray

X-ray photoemission spectroscopy of the 90 K superconductor Ba2YCu3O7−δ

1987 ◽  
Vol 2 (6) ◽  
pp. 768-774 ◽  
Author(s):  
Z. Iqbal ◽  
E. Leone ◽  
R. Chin ◽  
A. J. Signorelli ◽  
A. Bose ◽  
...  
Keyword(s):  
Core Level ◽  
Band Spectrum ◽  
Full Potential ◽  
Electronic Density ◽  
Augmented Plane Wave ◽  
X Ray ◽  
Superconducting Material ◽  
Auger Spectra ◽  
Linearized Augmented Plane Wave

The x-ray photoemission spectroscopie (XPS) data from different pelletized samples of the 90 K superconductor Ba2YCu3O7−δ (where δ∼0.2) have been obtained. The valence band spectrum (recorded at 300 and 170 K), which is composed of contributions from both the Cu 3d and O 2p levels, is compared with the full potential linearized augmented plane wave (FLAPW) calculated electronic density-of-states (DOS) reported by Massidda et al. and Mattheiss and Hamann. The experimental data indicate a relatively low DOS at the Fermi level. Detailed measurements of the core level Cu 2p, O 1s, Ba 3d, 4d, and Y 3d spectra of the superconducting and related standard materials, are presented. Data for the superconducting material were recorded in the freshly prepared form as well as after scraping in situ. The Cu 2p core level, satellite, and Auger spectra for the various samples were carefully examined in order to assess the possibility of the presence of Cu3+ ions in Ba2YCu3O7-δ. It is observed that surface reaction in air to form carbonates and hydroxides occurs readily in the superconducting material.

DICHROISM IN ANGLE-RESOLVED PHOTOEMISSION FROM Pt(111)

2002 ◽  
Vol 09 (02) ◽  
pp. 883-888 ◽  
Author(s):  
G. H. FECHER ◽  
J. BRAUN ◽  
A. OELSNER ◽  
CH. OSTERTAG ◽  
G. SCHÖNHENSE
Keyword(s):  
Circular Dichroism ◽  
Band Structure ◽  
Valence Band ◽  
Single Step ◽  
Core Level ◽  
X Ray ◽  
Photoelectron Diffraction ◽  
Band Emission ◽  
First Results ◽  
Circular Dichroïsm

The angular dependence of the circular dichroism in photoemission from Pt(111) was investigated for excitation with VUV and soft X-ray radiation. VUV excitation was used to probe band structure and the circular dichroism for valence band emission. The measurements are compared to full relativistic single step photoemission calculations. XPS was used to investigate the circular dichroism in emission from the 4f core level. In this case, the dichroism is induced by photoelectron diffraction. First results from single step core level calculations are compared to the experimental observations.

scholarly journals Influence of shallow core-level hybridization on the electronic structure of post-transition-metal oxides studied using soft X-ray emission and absorption

2003 ◽  
Vol 68 (16) ◽  
Author(s):  
Cormac McGuinness ◽  
Cristian B. Stagarescu ◽  
Philip J. Ryan ◽  
James E. Downes ◽  
Dongfeng Fu ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Transition Metal ◽  
Metal Oxides ◽  
Transition Metal Oxides ◽  
Core Level ◽  
X Ray
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