Investigations on electronic structure of YMnO3 by electron energy loss spectra and first-principle calculations

2019 ◽  
Vol 34 (4) ◽  
pp. 339-344
Author(s):  
S. Wang ◽  
J. Cai ◽  
H. D. Xu ◽  
H. L. Tao ◽  
Y. Cui ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Energy Loss ◽  
Experimental Spectrum ◽  
X Ray Diffraction ◽  
Edge Structure ◽  
Transmission Electron ◽  
The Individual ◽  
Electron Energy Loss ◽  
Electron Energy Loss Spectra ◽  
Good Agreement

Crystal structure and electronic structure of YMnO3 were investigated by X-ray diffraction and transmission electron microscopy related techniques. According to the density of states (DOS), the individual interband transitions to energy loss peaks in the low energy loss spectrum were assigned. The hybridization of O 2p with Mn 3d and Y 4d analyzed by the partial DOS was critical to the ferroelectric nature of YMnO3. From the simulation of the energy loss near-edge structure, the fine structure of O K-edge was in good agreement with the experimental spectrum. The valence state of Mn (+3) in YMnO3 was determined by a comparison between experiment and calculations.

scholarly journals Atomic scale crystal field mapping of polar vortices in oxide superlattices

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Sandhya Susarla ◽  
Pablo García-Fernández ◽  
Colin Ophus ◽  
Sujit Das ◽  
Pablo Aguado-Puente ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Energy Loss ◽  
Crystal Field ◽  
First Principles ◽  
Atomic Scale ◽  
First Principles Calculations ◽  
Edge Structure ◽  
Electron Energy Loss ◽  
Complex Polarization ◽  
Good Agreement

AbstractPolar vortices in oxide superlattices exhibit complex polarization topologies. Using a combination of electron energy loss near-edge structure analysis, crystal field multiplet theory, and first-principles calculations, we probe the electronic structure within such polar vortices in [(PbTiO3)16/(SrTiO3)16] superlattices at the atomic scale. The peaks in Ti $$L$$ L -edge spectra shift systematically depending on the position of the Ti4+ cations within the vortices i.e., the direction and magnitude of the local dipole. First-principles computation of the local projected density of states on the Ti $$3d$$ 3 d orbitals, together with the simulated crystal field multiplet spectra derived from first principles are in good agreement with the experiments.

Near-edge structure in electron-energy-loss spectra of MgO

1986 ◽  
Vol 33 (1) ◽  
pp. 22-24 ◽  
Author(s):  
Th. Lindner ◽  
H. Sauer ◽  
W. Engel ◽  
K. Kambe
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Edge Structure ◽  
Electron Energy Loss ◽  
Electron Energy Loss Spectra

A Novel Technique for Determining Local Dielectric Function During Ferroelectric to Paraelectric Phase Transformation in Barium Titanate with a Transmission Eels

1995 ◽  
Vol 404 ◽  
Author(s):  
Kalpana S Katti ◽  
Maoxu Qian ◽  
Mehmet Sarikaya
Keyword(s):  
Phase Transformation ◽  
Barium Titanate ◽  
Energy Loss ◽  
Electron Energy ◽  
Dielectric Function ◽  
Optical Parameters ◽  
Edge Structure ◽  
Transmission Electron ◽  
Electron Energy Loss

AbstractIn this work a transmission electron microscopy (TEM) technique was used in obtaining local dielectric properties calculated from optical parameters for dynamic investigation of the effect of cubic to tetragonal phase transformation in barium titanate. In order to obtain in situ local dielectric during phase transformation, Kramers-Kronig relations were applied using the transmission electron energy loss (EELS) measurements. The optical excitations in the EELS spectra were consistent with the band structure results. The Re (1/ε) (real part of the dielectric function) obtained from the energy loss data indicated a change at the phase transformation. A broadening of the valence plasmon excitation suggested an order-disorder nature to the cubic to tetragonal transformation. In situ electron energy loss near edge structure (ELNES) studies from 500–700 eV energy range near the O-K edge exhibited a pre-edge feature that is associated with the Ti-L1, edge which further indicates an order-disorder nature to the phase transformation. The significance of the results is discussed.

Electron energy-loss near-edge structure - a tool for the investigation of electronic structure on the nanometre scale

2001 ◽  
Vol 203 (2) ◽  
pp. 135-175 ◽  
Author(s):  
V. J. Keast ◽  
A. J. Scott ◽  
R. Brydson ◽  
D. B. Williams ◽  
J. Bruley
Keyword(s):  
Electronic Structure ◽  
Energy Loss ◽  
Electron Energy ◽  
Edge Structure ◽  
Electron Energy Loss

Structure of Frilled Carbon Nanowires Synthesized by Sulfur-assisted Chemical Vapor Deposition

2001 ◽  
Vol 706 ◽  
Author(s):  
Tadashi Mitsui ◽  
Takashi Sekiguchi ◽  
Mikka Nishitani-Gamo ◽  
Yafei Zhang ◽  
Toshihiro Ando
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Microwave Plasma ◽  
Chemical Vapor ◽  
Carbon Phase ◽  
Transmission Electron ◽  
Diamond Substrate ◽  
Thin Film Catalyst ◽  
Electron Energy Loss ◽  
Electron Energy Loss Spectra

AbstractEffects of hydrogen sulfide on the structure of carbon nanotubes (CNTs) were studied using high-resolution transmission electron microscopy (HRTEM) and electron energy loss spectroscopy (EELS). The CNTs were synthesized with an iron thin-film catalyst by microwave plasma-assisted CVD on the diamond substrate. The HRTEM images revealed that essentially all of the CNTs obtained in this study were multiwall (MWCNT). The addition of H2S resulted in nanotubes with split skins as cornhusks and/or frills. Electron energy loss spectra of the cornhusks indicated that they consist of sp2, sp3 and amorphous carbon phase. The spectra revealed that the sp3 to sp2 ratio at the points where cornhusks divide from the main stem was more than that at the edge of the cornhusks. No evidence of sulfur incorporation into the MWCNTs grown with the H2S addition was found. We speculate that the chemical nature of sulfur on the CNT growth yields such anomalous structure.

Microstructural features of Al-implanted 4H–SiC

2003 ◽  
Vol 18 (4) ◽  
pp. 772-779 ◽  
Author(s):  
C. M. Wang ◽  
Y. Zhang ◽  
W. J. Weber ◽  
W. Jiang ◽  
L. E. Thomas
Keyword(s):  
Energy Loss ◽  
State Energy ◽  
Rutherford Backscattering Spectrometry ◽  
Amorphous State ◽  
Red Shift ◽  
Edge Structure ◽  
Transmission Electron ◽  
Plasmon Loss ◽  
Highly Strained ◽  
Electron Energy Loss

The microstructural features of highly damaged 4H–SiC implanted with Al22+ ions at 450 K were studied using transmission electron microscopy (TEM) and electron energy-loss spectroscopy. Conventional TEM images reveal that the crystalline SiC domains are highly strained/distorted when the relative disorder on the Si sublattice ranges between about 0.4 and 0.8, as determined by Rutherford backscattering spectrometry in channeling geometry. As the relative disorder approaches 1.0, the high strain contrast appears to be relieved, and localized amorphized domains are observed. Plasmon-loss energy shows a red shift following the implantation, and the magnitude of the red shift increases with increasing relative disorder. Based on the red shift, the estimated volume expansion is approximately 8% for highly damaged crystalline SiC and approximately 16% for the amorphous state. Energy-loss near-edge-structure of both the C and Si K edge reveals the existence of Si–Si and C–C bonding in the Al22+ implanted SiC.

Electronic and Chemical Analysis of a Metal-Insulator Interface Utilizing Transmission Electron Energy Loss Spectroscopy at 5Å Spatial Resolution

1984 ◽  
Vol 41 ◽  
Author(s):  
Michael Scheinfein ◽  
Michael Isaacson
Keyword(s):  
Chemical Analysis ◽  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Valence Shell ◽  
Metal Insulator ◽  
Insulator Interface ◽  
Transmission Electron ◽  
Electron Energy Loss ◽  
Electron Energy Loss Spectra

AbstractUsing a 0.5 nm diameter probe of 100 keV electrons, we have been able to detect significant changes in the transmission electron energy loss spectra in the region of valence shell and L23 shell excitation within a spatial extent of 0.4 nm of an Al-AlF3 interface. The spectra have been recorded with a dose significantly less than the critical dose for destruction of the AlF3.

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