scholarly journals Electronic and optical properties of Ba(1-x)Ca(x) TiO3 and Ba(1-x)Sr(x)TiO3

2018 ◽  
Vol 3 (1) ◽  
Author(s):  
A. Belaaraj ◽  
O. Tahiri ◽  
S. Kassou ◽  
R. El Mrabet

The effect of Ca and Sr-doping on the structural electronic and optical properties of the cubic Ba1-xCaxTiO3 and Ba1-xSrxTiO3 (x=0.4, 0.6) mixed crystals was investigated using first-principles calculations based on density functional theory (DFT). The calculated band structures based on the optimized geometry of the cell for the solid solutions show an indirect band gap character at M-points, with low energy dispersion along height symmetry directions in the Brillouin zone. The band gaps increase with Ca and Sr concentrations. The total and partial densities of states were analyzed to examine the contribution of different orbitals to the maximum of valence band and the minimum of the conduction band. The optical properties such as reflectivity, energy loss, refractive index and extinction coefficient were studied. #DFT_calculations #band_gap #density_of_states #optical_properties

2011 ◽  
Vol 216 ◽  
pp. 341-344 ◽  
Author(s):  
Qi Jun Liu ◽  
Zheng Tang Liu ◽  
Li Ping Feng

Electronic structure, effective masses and optical properties of monoclinic HfO2were studied using the plane-wave ultrasoft pseudopotential technique based on the first-principles density-functional theory (DFT). The calculated equilibrium lattice parameters are in agreement with the previous works. From the band structure, the effective masses and optical properties are obtained. The calculated band structure shows that monoclinic HfO2has indirect band gap and all of the effective masses of electrons and holes are less than that of a free electron. The peaks position distributions of imaginary parts of the complex dielectric function have been explained according to the theory of crystal-field and molecular-orbital bonding.


RSC Advances ◽  
2019 ◽  
Vol 9 (70) ◽  
pp. 41058-41065 ◽  
Author(s):  
Tuan V. Vu ◽  
Hien D. Tong ◽  
Duy Phu Tran ◽  
Nguyen T. T. Binh ◽  
Chuong V. Nguyen ◽  
...  

In the present work, we investigate systematically the electronic and optical properties of Janus ZrSSe using first-principles calculations.


2011 ◽  
Vol 197-198 ◽  
pp. 487-490 ◽  
Author(s):  
Li Ping Feng ◽  
Zheng Tang Liu ◽  
Qi Jun Liu

Structural, electronic and optical properties of 2H-CuAlO2 were computed, using the plane-wave ultrasoft pseudopotential technique based on the first-principles density functional theory (DFT). The equilibrium lattice parameters, band structure, densities of states (DOS) and charge densities of 2H-CuAlO2 have been obtained. The equilibrium lattice parameters, band structure and DOS are found to be in good agreement with the available experimental and calculational values. The charge densities and the chemical bonding of 2H-CuAlO2 are analyzed, which show that bonding between Cu and O is mainly covalent due to Cu 3d and O 2p hybridization and that bonding between Al and O is mainly ionic. The complex dielectric function, refractive index and absorption coefficient of 2H-CuAlO2 have been predicted. The calculated static dielectric constant and static refractive index of 2H-CuAlO2 is 7.1 and 2.66, respectively.


RSC Advances ◽  
2016 ◽  
Vol 6 (13) ◽  
pp. 10919-10929 ◽  
Author(s):  
Long-Juan Kong ◽  
Guang-Hua Liu ◽  
Yu-Jun Zhang

The electronic and optical properties of phosphorene co-doped with vanadium and non-metallic atoms (B, C, N and O) are investigated by employing first-principles calculations based on density functional theory.


2015 ◽  
Vol 33 (1) ◽  
pp. 169-174 ◽  
Author(s):  
Shen Tao ◽  
Hu Chao ◽  
Dai Hailong ◽  
Yang Wenlong ◽  
Liu Hongchen ◽  
...  

AbstractFirst principles calculations have been performed to investigate the structure, electronic and optical properties of Y3Fe5O12. Both the cubic and trigonal phases have been considered in our calculation. The calculated structural parameters are slightly larger than the experimental values. The band structures show that Y3Fe5O12 in cubic and trigonal phases have direct band gaps of 0.65 and 0.17 eV. The calculations of dielectric function, absorption, extinction coefficient, refractive index, energy loss function and reflectivity are presented.


2013 ◽  
Vol 373-375 ◽  
pp. 1965-1969
Author(s):  
Kun Nan Qin ◽  
Ling Zhi Zhao ◽  
Yong Mei Liu ◽  
Fang Fang Li ◽  
Chao Yang Cui

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.


Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 978
Author(s):  
Henry Igwebuike Eya ◽  
Esidor Ntsoenzok ◽  
Nelson Y. Dzade

Transition metal perovskite chalcogenides are attractive solar absorber materials for renewable energy applications. Herein, we present the first–principles screened hybrid density functional theory analyses of the structural, elastic, electronic and optical properties of the two structure modifications of strontium zirconium sulfide (needle–like α–SrZrS3 and distorted β–SrZrS3 phases). Through the analysis of the predicted electronic structures, we show that both α– and β–SrZrS3 materials are direct band gaps absorbers, with calculated band gaps of 1.38, and 1.95 eV, respectively, in close agreement with estimates from diffuse–reflectance measurements. A strong light absorption in the visible region is predicted for the α– and β–SrZrS3, as reflected in their high optical absorbance (in the order of 105 cm−1), with the β–SrZrS3 phase showing stronger absorption than the α–SrZrS3 phase. We also report the first theoretical prediction of effective masses of photo-generated charge carriers in α– and β–SrZrS3 materials. Predicted small effective masses of holes and electrons at the valence, and conduction bands, respectively, point to high mobility (high conductivity) and low recombination rate of photo-generated charge carriers in α– and β–SrZrS3 materials, which are necessary for efficient photovoltaic conversion.


2014 ◽  
Vol 900 ◽  
pp. 203-208 ◽  
Author(s):  
Ting Ting Shao ◽  
Fu Chun Zhang ◽  
Wei Hu Zhang

The structural, electronic, and optical properties of rutile-type SnO2 are studied by plane-wave pseudopotential density functional theory (DFT) with GGA, LDA, B3LYP and PBE0 respectively. The computing results show that the band gap getting from PBE0 and B3LYP is much more consistent with the available experimental data than that from GGA and LDA, no matter what the latter use ultra-soft pseudopotential or norm conserving pseudopotential. However, the density of state, real part and imaginary part of dielectric function calculating from every type is basically similar in qualitative analysis.


2020 ◽  
Author(s):  
Messaoud Caid

An investigation into the structural, electronic and optical properties of superlattices(SLs) (ZnSe)n/(ZnTe)n was conducted using first principles calculations based on density functional theory (DFT). The total energies were calculated within the full-potential linear muffin-tin orbital (FP-LMTO) method augmented by a plane-wave basis (PLW), implemented in LmtART 7.0 code. The effects of the approximations to the exchange-correlation energy were treated by the local density approximation (LDA). The ground state properties of (ZnSe)n/(ZnTe)n binary compounds are determined and compared with the available data. It is found that the superlattice (n-n: 1-1, 2-2 and 3-3) band gaps vary depending on the layers used. The optical constants, including the dielectric function ε(w), the refractive index n(w) and the reflectivity R(w), are calculated for radiation energies up to 35eV.


2016 ◽  
Vol 4 (42) ◽  
pp. 10082-10089 ◽  
Author(s):  
Xianping Chen ◽  
Xiang Sun ◽  
D. G. Yang ◽  
Ruishen Meng ◽  
Chunjian Tan ◽  
...  

The structure along with the electronic and optical properties of a SiGe/BN monolayer heterostructure were theoretically researched using density functional theory calculations.


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