scholarly journals Investigation of nickel lattice sites in diamond: Density functional theory and x-ray absorption near-edge structure experiments

2012 ◽  
Vol 86 (5) ◽  
Author(s):  
Etienne Gheeraert ◽  
Amit Kumar ◽  
Etienne Bustarret ◽  
Laurent Ranno ◽  
Laurence Magaud ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Functional Theory ◽  
Edge Structure ◽  
X Ray ◽  
X Ray Absorption

scholarly journals Oxygen vacancies induced photoluminescence in $$\hbox {SrZnO}_2$$ nanophosphors probed by theoretical and experimental analysis

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Manju ◽  
Megha Jain ◽  
Saibabu Madas ◽  
Pargam Vashishtha ◽  
Parasmani Rajput ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Band Structure ◽  
Density Functional ◽  
Oxygen Vacancies ◽  
Defect States ◽  
Functional Theory ◽  
Edge Structure ◽  
X Ray ◽  
New Energy ◽  
X Ray Absorption

Abstract We report, for the first time, the influence of oxygen vacancies on band structure and local electronic structure of $$\hbox {SrZnO}_2$$ SrZnO 2 (SZO) nanophosphors by combined first principle calculations based on density functional theory and full multiple scattering theory, correlated with experimental results obtained from X-ray absorption and photoluminescence spectroscopies. The band structure analysis from density functional theory revealed the formation of new energy states in the forbidden gap due to introduction of oxygen vacancies in the system, thereby causing disruption in intrinsic symmetry and altering bond lengths in SZO system. These defect states are anticipated as origin of observed photoluminescence in SZO nanophosphors. The experimental X-ray absorption near edge structure (XANES) at Zn and Sr K-edges were successfully imitated by simulated XANES obtained after removing oxygen atoms around Zn and Sr cores, which affirmed the presence and signature of oxygen vacancies on near edge structure.

scholarly journals Local and electronic structure around Ga in CdTe: evidence of DX- and A-centers

2012 ◽  
Vol 20 (1) ◽  
pp. 166-171
Author(s):  
Vasil Koteski ◽  
Jelena Belošević-Čavor ◽  
Petro Fochuk ◽  
Heinz-Eberhard Mahnke
Keyword(s):  
Density Functional ◽  
Plane Waves ◽  
Lattice Relaxation ◽  
Defect Structures ◽  
Functional Theory ◽  
Edge Structure ◽  
X Ray ◽  
First Time ◽  
X Ray Absorption ◽  
Good Agreement

The lattice relaxation around Ga in CdTe is investigated by means of extended X-ray absorption spectroscopy (EXAFS) and density functional theory (DFT) calculations using the linear augmented plane waves plus local orbitals (LAPW+lo) method. In addition to the substitutional position, the calculations are performed for DX- and A-centers of Ga in CdTe. The results of the calculations are in good agreement with the experimental data, as obtained from EXAFS and X-ray absorption near-edge structure (XANES). They allow the experimental identification of several defect structures in CdTe. In particular, direct experimental evidence for the existence of DX-centers in CdTe is provided, and for the first time the local bond lengths of this defect are measured directly.

Electronic, magnetic, vibrational, and X-ray spectroscopy of inverse full-Heusler Fe2IrSi alloy

2021 ◽  
Author(s):  
Lalrinkima ◽  
C. E. Ekuma ◽  
T. C. Chibueze ◽  
L. A. Fomin ◽  
I. V. Malikov ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Absorption Spectroscopy ◽  
Density Functional ◽  
Functional Theory ◽  
X Ray ◽  
X Ray Absorption ◽  
Full Heusler

The electronic, magnetic, structural, vibrational, and X-ray absorption spectroscopy of inverse full-Heusler Fe2IrSi alloy has been studied from density functional theory (DFT). The XA-phase with FM-configuration is the most stable one, structurally and thermodynamically.

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