scholarly journals Effect of Electronic Correlations on the Electronic Structure, Magnetic and Optical Properties of the Ternary RCuGe Compounds with R = Tb, Dy, Ho, Er

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3536
Author(s):  
Alexey V. Lukoyanov ◽  
Lubov N. Gramateeva ◽  
Yury V. Knyazev ◽  
Yury I. Kuz’min ◽  
Sachin Gupta ◽  
...  
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
Theoretical Calculations ◽  
Rare Earth Ions ◽  
Local Spin Density Approximation ◽  
Electron Correlations ◽  
Absorption Region ◽  
Densities Of States ◽  
Interband Light Absorption ◽  
Good Agreement

In this study, the ab initio and experimental results for RCuGe ternary intermetallics were reported for R = Tb, Dy, Ho, Er. Our theoretical calculations of the electronic structure, employing local spin density approximation accounting for electron–electron correlations in the 4f shell of Tb, Dy, Ho, Er ions were carried in DFT+U method. The optical properties of the RCuGe ternary compounds were studied at a broad range of wavelengths. The spectral and electronic characteristics were obtained. The theoretical electron densities of states were taken to interpret the experimental energy dependencies of the experimental optical conductivity in the interband light–absorption region. From the band calculations, the 4f shell of the rare-earth ions was shown to provide the major contribution to the electronic structure, magnetic and optical properties of the RCuGe intermetallics. The accounting for electron–electron correlations in Tb, Dy, Ho, Er resulted in a good agreement between the calculated and experimental magnetic and optical characteristics.

ELECTRONIC STRUCTURE AND OPTICAL PROPERTIES OF CRYSTALLINE C60

1992 ◽  
Vol 06 (06) ◽  
pp. 309-321 ◽  
Author(s):  
W.Y. CHING ◽  
MING-ZHU HUANG ◽  
YONG-NIAN XU ◽  
FANQI GAN
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
First Principles ◽  
Optical Spectrum ◽  
Local Density ◽  
Low Dielectric Constant ◽  
Experimental Measurements ◽  
Absorption Bands ◽  
Low Dielectric ◽  
Good Agreement

The electronic structure and optical properties of crystalline C 60 and their pressure dependence have been studied by first-principles local density calculations. It is shown that fcc C 60 has a low dielectric constant and an optical spectrum rich in structures. The spectrum shows five disconnected absorption bands in the 1.4 to 7.0 eV region with sharp structures in each band that can be attributed to critical point transitions. This is a manifestation of the localized molecular structure coupled with long range crystalline order unique to the C 60 crystal. At a sufficient high pressure, the structures in the optical spectrum start to merge due to the merging of the bands. These results are in good agreement with some recent experimental measurements.

First Principles Calculations of Electronic Structure and Optical Properties of Cu-Doped SnS2

2013 ◽  
Vol 373-375 ◽  
pp. 1965-1969
Author(s):  
Kun Nan Qin ◽  
Ling Zhi Zhao ◽  
Yong Mei Liu ◽  
Fang Fang Li ◽  
Chao Yang Cui
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
First Principles ◽  
Density Functional ◽  
Optical Absorption Coefficient ◽  
Impurity Level ◽  
First Principles Calculations ◽  
Absorption Region ◽  
Functional Theory ◽  
The Density Functional Theory

The electronic structure and optical properties of Cu-doped SnS2with Sn-substituted content of 0, 12.5 and 37.5 at.% were successfully calculated by the first principles plane-wave pseudopotentials based on the density functional theory. It is found that the intermediate belts appear near the Fermi level and the energy band gap becomes narrower after the doping of the Cu atoms. The absorption peaks show a remarkable redshift and the absorption region broadens relatively after introducing acceptor impurity level. When Sn atoms of 37.5 at% were substituted by Cu, the optical absorption coefficient is significantly improved in the frequency range below 5.58 eV and over 8.13 eV.

scholarly journals Optical and electronic properties of lithium thiogallate (LiGaS2): experiment and theory

RSC Advances ◽  
2020 ◽  
Vol 10 (45) ◽  
pp. 26843-26852
Author(s):  
Tuan V. Vu ◽  
A. A. Lavrentyev ◽  
B. V. Gabrelian ◽  
Dat D. Vo ◽  
Pham D. Khang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
Electronic Properties ◽  
Theoretical Calculations ◽  
Optical And Electronic Properties

We report the relation between the optical properties and electronic structure of lithium thiogallate (LiGaS2) by performing XPS and XES measurements and theoretical calculations.

Comparative study of the electronic structure and optical properties of the Heusler alloys Co2MGa and Co2MAl (M = Fe and Ni)

2021 ◽  
Author(s):  
E. I. Shreder ◽  
A. A. Makhnev ◽  
K. G. Suresh ◽  
M. G. Kostenko ◽  
E. D. Chernov ◽  
...  
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
Spin Polarization ◽  
Energy Gap ◽  
Magnetic Moments ◽  
Heusler Alloys ◽  
Complex Dielectric Constant ◽  
Spectral Parameters ◽  
Spectrum Region ◽  
Good Agreement

The electronic structure and optical properties of the Heusler alloys Co2NiGa, Co2NiAl, Co2FeGa, and Co2FeAl are reported and compared in this work. In the Fe-based alloys, Co2FeGa and Co2FeAl, the electronic structure is found to have 100% spin polarization with the indirect energy gap in the [Formula: see text]-[Formula: see text] direction, whereas in Co2NiGa and Co2NiAl, the density of states is metallic in both spin projections with spin polarization of 55% (Co2NiGa) and 37% (Co2NiAl). Total and Co partial magnetic moments of all Heusler alloys for the optimized lattice parameters were found in a good agreement with previous calculations and experimental data. The frequency dependence of the real and imaginary parts of the complex dielectric constant for the Heusler alloys is studied in the spectrum region of 0.08–5 eV. The research results are discussed based on the performed calculations of the electronic structure. It was found that the character of variations of the spectral parameters of the alloys is typical for media with the metallic conductivity. In the IR region, the mechanism of the intraband acceleration of electrons by the light wave field dominates. The significant changes in the optical spectrum, magnetic moment, spin polarization and electronic structure were revealed in Co2MGa and Co2MAl for different M atoms which motivate further investigations of the Co-based Heusler alloys as promising materials for spintronics.

Ligand Substitution Effect on Optical Properties in Conducting Tetraazaporphyrines

1995 ◽  
Vol 393 ◽  
Author(s):  
Liqun Guo ◽  
D. E. Ellis ◽  
O. V. Gubanova ◽  
B. M. Hoffman
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
Density Functional ◽  
Substitution Effect ◽  
Ligand Substitution ◽  
High Symmetry ◽  
Double Peak ◽  
Densities Of States ◽  
Self Consistent ◽  
Spin Distributions

ABSTRACTSelf-consistent Density Functional calculations have been performed on a variety of planar conjugated Ni-centered macrocycles with a basic tetraazaporphyrinic core and dithiolene groups (PZ) or fused-benzo groups (PC). Theoretical energy diagrams, charge and spin distributions and densities of states have been obtained in order to understand the electronic structure modifications due to peripheral ligand substitution. The substituents role in altering electronic properties and charge distribution of the porphyrazine macrocycles has been used to interpret the observed variations in optical absorption profiles. In the Q-band (∼ 680 nm) region, a single peak is seen for high symmetry (D4h) macrocycles and a double peak for lower symmetry (D2h and C2v) systems. Calculated intensities and band splittings are compared in detail with qualitative molecular orbital models and experiment in the visible and UV regions. Predictions are made for the infrared absorption and semiconducting band gap.

Optical Properties and Electronic Structure of LaNi5-XCux (x=0–1.2) Intermetallic System

2010 ◽  
Vol 168-169 ◽  
pp. 529-532 ◽  
Author(s):  
Yu.V. Knyazev ◽  
Y.I. Kuz’min ◽  
A.V. Lukoyanov ◽  
Anatoly G. Kuchin
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
Optical Conductivity ◽  
Theoretical Calculations ◽  
Generalized Gradient ◽  
Broad Absorption ◽  
Generalized Gradient Approximation ◽  
Electron Transitions ◽  
Intermetallic System ◽  
Conductivity Spectra

Optical properties of the LaNi5-xCux (x = 0, 0.6, 1, 1.2) compounds were studied. It was shown that substitution of copper for nickel led to noticeable changes in the optical conductivity spectra. Calculations of the electronic structure of compounds with x = 0, 1, 2 were performed using a generalized gradient approximation. The interband optical conductivity of these intermetallics was calculated. The optical ellipsometrical measurements and theoretical calculations testify to the appearance of a broad absorption structure associated with the Cu 3d  Ni 3d electron transitions and increasing with the growth of copper content.

Electronic Structure and Associated Optical Properties of LAPO4:Ce

1994 ◽  
Vol 348 ◽  
Author(s):  
K. C. Mishra ◽  
K. H. Johnson
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
Green Emission ◽  
Scattered Wave ◽  
Cluster Approach ◽  
Small Magnitude ◽  
Lanthanum Phosphate ◽  
Consistent Field ◽  
Self Consistent Field ◽  
Good Agreement

ABSTRACTLanthanum phosphate activated by cerium and terbium is a well known lamp phosphor which is used for its green emission. In this paper, we have investigated the electronic structure and associated optical properties of lanthanum phosphate doped with cerium using the self consistent field scattered wave molecular orbital cluster approach. Relativistic corrections are included for the lanthanum and cerium centered clusters. In spite of the small magnitude of crystal field splitting, a significant admixture of the f-like orbitals with the ligand orbitals is observed for cerium. The optical transitions are calculated using the transition state formalism. The absorption peaks due to electronic transition from the f-like states to d-like states of cerium are found to be 271 rim, 259 nm, 245 nm, 208 nm and 194 nm which are in good agreement with the experiment. The nature of the band gap transition in lanthanum phosphate is also discussed.

Band Structure and Optical Properties of CuInSe2

2014 ◽  
Vol 894 ◽  
pp. 254-258
Author(s):  
Rong Zhen Chen ◽  
Clas Persson
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
Coupling Effect ◽  
Full Potential ◽  
Spin Orbit Coupling ◽  
Generalized Gradient ◽  
Augmented Plane Wave ◽  
Generalized Gradient Approximation ◽  
Linearized Augmented Plane Wave ◽  
Good Agreement

In this work, the electronic structure and dielectric function of chalcopyrite CuInSe2 are presented. The results are based on the full-potential linearized augmented plane wave (FPLAPW) method using the generalized gradient approximation (GGA) plus an onsite Coulomb interaction U of the Cu d states. The dielectric constant, absorption coefficient and refractive index are explored by means of optical response. The spin-orbit coupling effect is considered for the calculations of electronic structure and optical properties. We find that the results based on our calculation method have good agreement compared with experimental and other earlier simulations results.

scholarly journals Electronic and magneto-optical properties of ZnO:Co

2018 ◽  
Vol 185 ◽  
pp. 06012
Author(s):  
Erkin Kulatov ◽  
Oleg Novodvorskii ◽  
Andrey Lotin ◽  
Vladimir Rylkov ◽  
Elena Gan’shina ◽  
...  
Keyword(s):  
Experimental Data ◽  
Thin Films ◽  
Optical Properties ◽  
Kerr Effect ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Theoretical Data ◽  
Functional Theory ◽  
Type Crystal ◽  
Good Agreement

High-quality ZnO:Co thin films were synthesized on the sapphire (0001) substrates by pulsed laser deposition. XRD result reveals that the Zn1-xCoxO films are of wurtzite-type crystal structure with x up to x = 0.35. The structural, optical and magnetic properties of ZnO:Co thin films are studied by experiments and theoretical calculations. Electronic structure of ZnO:Co with native defects are studied by the first-principles density functional theory. The experimental data and theoretical data have demonstrated quite good agreement. The optical and magneto-optical properties, namely, on-and off-diagonal conductivity tensor and the transversal Kerr effect (TKE), are calculated for comparison with available experimental data. The origin of observed TKE peaks is discussed..

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