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.

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.

The Effect of Local Symmetry on Atomic Resolution EELS Near-Edge Structures: Predictions for Grain Boundaries In NiAl

2000 ◽  
Vol 6 (S2) ◽  
pp. 186-187
Author(s):  
D. A. Pankhurst ◽  
G. A. Botton ◽  
C. J. Humphreys
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Local Density ◽  
Spherical Aberration ◽  
Core Loss ◽  
Atomic Scale ◽  
Atomic Resolution ◽  
Atomic Column ◽  
Edge Structure ◽  
Electron Energy Loss

It has been demonstrated that electron energy loss spectrometry (EELS) can be used to probe the electronic structure of materials on the near-atomic scale. The electron energy loss near edge structure (ELNES) observed after the onset of a core edge reflects a weighted local density of final states to which core electrons are excited by fast incident electrons. Lately ‘atomic resolution EELS’ and ‘column-by-column spectroscopy’ have become familiar themes amongst the EELS community. The next generation of STEMs, equipped with spherical aberration (Cs) correctors and electron beam monochromators, will have sufficient spatial and energy resolution, along with the superior signal to noise required, to detect small changes in the ELNES from atomic column to atomic column.Core loss ELNES provides information about unoccupied states, but the structure observed in spectra is sensitive to changes in the underlying occupied states, and thus to the bonding in the material.

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

Strain induced atomic structure at the Ir-doped LaAlO3/SrTiO3 interface

2017 ◽  
Vol 19 (42) ◽  
pp. 28676-28683 ◽  
Author(s):  
M. Lee ◽  
R. Arras ◽  
B. Warot-Fonrose ◽  
T. Hungria ◽  
M. Lippmaa ◽  
...  
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Atomic Structure ◽  
Electron Energy Loss Spectroscopy ◽  
First Principles ◽  
Strain State ◽  
First Principles Calculations ◽  
Electron Energy Loss ◽  
Different Levels

Different levels of Ir doping at the LaAlO3/SrTiO3 interface affect the strain state in LaAlO3, as investigated using atomically resolved microscopy (HAADF-STEM), electron energy loss spectroscopy (EELS) and first-principles calculations (DFT).

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