scholarly journals Electronic and optical properties of Mn–S co-doped anatase TiO2 from first-principles calculations

2016 ◽  
Vol 34 (1) ◽  
pp. 38-44 ◽  
Author(s):  
Guohao Wu ◽  
S.K. Zheng ◽  
Xiaobing Yan
Keyword(s):  
Optical Properties ◽  
Visible Light ◽  
Density Functional ◽  
Density Functional Method ◽  
Functional Method ◽  
Potential Candidate ◽  
Generalized Gradient ◽  
Electronic And Optical Properties ◽  
Enhanced Absorption ◽  
Co Doped

AbstractThe electronic and optical properties of Mn–S co-doped anatase TiO2 were calculated using the plane-wave-based ultrasoft pseudopotential density functional method within its generalized gradient approximation (GGA). The calculated results show that the band gap of Mn–S co-doped TiO2 is larger than that of the pure TiO2, and two impurity bands appear in the forbidden band, one of which above the valence band plays a vital role for the improvement of the visible light catalytic activity. The Mn–S co-doped anatase TiO2 could be a potential candidate for a photo catalyst because of its enhanced absorption ability of visible light.

scholarly journals Structural, electronic and optical properties of PtSe2-InSe van der Waals heterostructures

2021 ◽  
Author(s):  
Zang yu
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Van Der Waals ◽  
Interlayer Coupling ◽  
Full Potential ◽  
Potential Candidate ◽  
Generalized Gradient ◽  
Van Der Waals Heterostructures ◽  
Electronic And Optical Properties ◽  
Total Energies

We studied the structural, electronic and optical properties of PtSe2/InSe van der Waals heterostructures (vdWh) using first principles calculations based on density functional theory (DFT). The total energies were calculated within the full-potential linearized augmented plane wave (FP-LAPW) method within the generalized gradient approximation (GGA) for the exchange-correlation potential. It is found that the PtSe2/InSe vdWh band gaps vary tunable via changing the interlayer coupling. 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 50 eV. This vdWh seem to be a potential candidate of optoelectronic devices.

Density functional theory study of the effect of Vanadium doping on electronic and optical properties of NiO

2019 ◽  
Vol 08 (02) ◽  
pp. 1950007
Author(s):  
Fidele J. Twagirayezu
Keyword(s):  
Density Functional Theory ◽  
Optical Properties ◽  
Density Functional ◽  
Optical Transition ◽  
Function Analysis ◽  
Potential Candidate ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Electronic And Optical Properties ◽  
Vanadium Doping

The effect of Vanadium (V) doping on electronic and optical properties of NiO is discussed. Electronic and optical properties of a 32-atom supercell of V[Formula: see text]Ni[Formula: see text]O [Formula: see text] obtained from first-principles calculations, performed within density functional theory (DFT), using the generalized gradient approximation (GGA) with the Hubbard potential [Formula: see text] were studied and compared to those of a 32-atom supercell of pure NiO. From the electronic structure and complex dielectric function analysis, the V doping causes the reduction of the bandgap by inducing the localized V [Formula: see text] state in the NiO bandgap region, and the first optical transition for V-doped NiO occurs at a lower frequency than the one for the intrinsic NiO. The bandgap shrinkage to about 2 eV makes NiO when doped with V a potential candidate for visible light range application in photocatalytic applications. The resulting effects on refractive index, reflectivity, absorption, optical conductivity and loss function for V-doped NiO are compared to those of pristine NiO.

Optical Properties of Heterodiamond BC3 from First-Principles

2013 ◽  
Vol 749 ◽  
pp. 551-555 ◽  
Author(s):  
Lei Li ◽  
Wen Xue Li ◽  
Dong Han ◽  
She Wei Xin ◽  
Yi Yang ◽  
...  
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Density Functional ◽  
Density Functional Method ◽  
Functional Method ◽  
First Principles Calculation ◽  
Optical Absorption Coefficient ◽  
Generalized Gradient ◽  
Exchange Correlation ◽  
Electron Deficiency

First principles calculation for optical properties of a tetragonal BC3 (t-BC3) are performed through the pseudopotential density functional method. The exchange correlation potential is treated by the Perdew-Burke-Eruzerhof form of generalized gradient approximation. The basic optical constants including the real and imaginary parts of the dielectric function, the optical absorption coefficient, the reflectivity and the energy loss function were calculate in detail by this method. The results indicate that the t-BC3 is an optical anisotropic crystal and its electron-deficiency characteristic can cause some features in low energy region.

Anion-Cation Replacement Effect on the Structural and Optoelectronic Properties of the LiMX2 (M = Al, Ga, In; X = S, Se, Te) Compounds: A First Principles Study

2018 ◽  
Vol 73 (7) ◽  
pp. 645-655 ◽  
Author(s):  
Amjad Khan ◽  
M. Sajjad ◽  
G. Murtaza ◽  
A. Laref
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Density Functional Method ◽  
Covalent Bond ◽  
Functional Method ◽  
Generalized Gradient ◽  
Lattice Constants ◽  
Crystal Unit Cell ◽  
Ionic Bonds ◽  
Structural And Optoelectronic Properties

AbstractIn the chalcopyrite (or tetragonal) phase, different physical properties of the ternary LiMX2 (M = Al, Ga, In and X = S, Se, Te) compounds are studied by the very accurate density functional method. The optimized lattice constants and the bandgaps are close to the existing experimental data. In addition, for most of the LiMX2 compounds, when the cations change from Al to In and anions from S to Te, the lattice constant and equilibrium volume for the crystal unit cell increase whereas the bulk modulus decreases. Using different generalized gradient approximations, the band structure calculations are performed. Generally, it was observed that there exists a decreasing tendency of the bandgap energies except for the LiAlSe2, LiInSe2, and LiGaTe2 compounds due to the change from Al to In as well as the change from S to Te. The bonding analysis shows that ionic bonds are present between the Li-X atoms, while a covalent bond exists between the M cations and X anions. The optical properties of the compounds are studied by calculating the real and imaginary components of the refractive index, reflectivity, optical conductivity, and birefringence. In addition, the optical properties from the calculations show that these materials are appropriate applicants to be utilized as Bragg’s reflector or applied in optoelectronic and solar cell technology.

First principles calculations of structural, electronic and optical properties of InN compound

2015 ◽  
Vol 29 (05) ◽  
pp. 1550028 ◽  
Author(s):  
R. Graine ◽  
R. Chemam ◽  
F. Z. Gasmi ◽  
R. Nouri ◽  
H. Meradji ◽  
...  
Keyword(s):  
Optical Properties ◽  
Band Structure ◽  
Density Functional ◽  
Local Density ◽  
Indium Nitride ◽  
Alternative Form ◽  
Full Potential ◽  
Generalized Gradient ◽  
Pressure Derivative ◽  
Electronic And Optical Properties

We carried out ab initio calculations of structural, electronic and optical properties of Indium nitride ( InN ) compound in both zinc blende and wurtzite phases, using the full-potential linearized augmented plane wave method (FP-LAPW), within the framework of density functional theory (DFT). For the exchange and correlation potential, local density approximation (LDA) and generalized gradient approximation (GGA) were used. Moreover, the alternative form of GGA proposed by Engel and Vosko (EV-GGA) and modified Becke–Johnson schemes (mBJ) were also applied for band structure calculations. Ground state properties such as lattice parameter, bulk modulus and its pressure derivative are calculated. Results obtained for band structure of these compounds have been compared with experimental results as well as other first principle computations. Our results show good agreement with the available data. The calculated band structure shows a direct band gap Γ → Γ. In the optical properties section, several optical quantities are investigated; in particular we have deduced the interband transitions from the imaginary part of the dielectric function.

Structural Electronic and Optical Properties of MgO, CaO and SrO Binary Compounds: Comparison Study

2016 ◽  
Vol 257 ◽  
pp. 123-126 ◽  
Author(s):  
Salima Labidi ◽  
Jazia Zeroual ◽  
Malika Labidi ◽  
Kalthoum Klaa ◽  
Rachid Bensalem
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Density Functional ◽  
Local Density ◽  
Alternative Form ◽  
Full Potential ◽  
Generalized Gradient ◽  
Electronic And Optical Properties ◽  
Optical Dielectric Constant ◽  
Reported Data

First-principles calculations for electronic and optical properties under pressure effect of MgO, SrO and CaO compounds in the cubic structure, using a full relativistic version of the full-potential augmented plane-wave (FP-LAPW) method based on density functional theory, within the local density approximation (LDA) and the generalized gradient approximation (GGA), have been reported. Furthermore, band structure calculations have been investigated by the alternative form of GGA proposed by Engel and Vosko (GGA-EV) and modified by Becke-Johnson exchange correlation potential (MBJ-GGA). All calculated equilibrium lattices, bulk modulus and band gap at zero pressure are find in good agreement with the available reported data. The pressure dependence of band gap and the static optical dielectric constant are also investigated in this work.

DEFECT FORMATION AND MAGNETIC PROPERTIES OF Co-DOPED ZnO NANOWIRES

NANO ◽  
2013 ◽  
Vol 08 (02) ◽  
pp. 1350021 ◽  
Author(s):  
LI BIN SHI ◽  
GUO QUAN QI ◽  
YING FEI
Keyword(s):  
Magnetic Properties ◽  
Density Functional ◽  
Defect Formation ◽  
Density Functional Method ◽  
Zno Nanowires ◽  
Generalized Gradient ◽  
Surface Sites ◽  
Doped Zno ◽  
Formation Energies ◽  
Co Doped

The defect formation energies and magnetic properties in Co -doped ZnO nanowires (NWs) are studied using the first-principle density functional method within the generalized gradient approximation (GGA) and GGA + U schemes. It is found that Co impurity has lower formation energies in the surface sites, indicating that Co impurity occupies preferably surface sites of NWs. Ferromagnetic (FM) and antiferromagnetic (AFM) coupling are investigated by GGA and GGA + U methods. The results show that the AFM coupling in energy is lower than the FM coupling, which indicates that AFM coupling is more stable. The magnetic properties can be mediated by the vacancies [ VO(B) and VZn(B) ] and interstitials [ IZn(oct) ]. The stability of the FM and AFM can be explained by the Co 3d energy level coupling.

scholarly journals Origin of Visible Light Photocatalytic Activity of Ag3AsO4from First-Principles Calculation

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Yan Gong ◽  
Hongtao Yu ◽  
Xie Quan
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Density Functional ◽  
Photocatalytic Performance ◽  
Density Functional Method ◽  
Functional Method ◽  
First Principles Calculation ◽  
Visible Light Photocatalytic Activity ◽  
Valence Bands ◽  
Visible Light Photocatalytic

Recently a novel sliver oxide Ag3AsO4has been found to be an excellent photocatalyst with strong oxidation capability for pollutant degradation under visible light. But the origin of its high visible light photocatalytic activity was unclear which hindered further research of Ag3AsO4. For clarifying that, the electronic structure and optical properties of Ag3AsO4have been analyzed by the hybrid density functional method. The results reveal that the Ag3AsO4presents a narrow band gap with strong oxidation ability of the valence bands maximum edge and the highly delocalized charge distribution of the conduction bands minimum is beneficial for the carriers transfer to surface to participate in the photocatalytic reaction. These results provide clear explanations of the excellent visible light photocatalytic performance of the Ag3AsO4from microscopic aspect. And it is significant to design novel materials with high photocatalytic performance.

Density Functional Study of the Electronic, Elastic and Optical Properties of Bi2O2Te

2019 ◽  
Vol 75 (1) ◽  
pp. 73-80 ◽  
Author(s):  
Jia-Xin Chen ◽  
Xiao-Ge Zhao ◽  
Xing-Xing Dong ◽  
Zhen-Long Lv ◽  
Hong-Ling Cui
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Density Functional Method ◽  
Uniaxial Crystal ◽  
Functional Method ◽  
Functional Study ◽  
Layered Crystal ◽  
High Electron ◽  
Covalent Interactions ◽  
Zero Frequency

AbstractLayered crystal Bi2O2Te has recently been found to have high electron mobility and excellent thermoelectric properties for technical applications; however, its other properties are not well studied yet. In this work, the electronic, elastic and optical properties of Bi2O2Te are systematically studied using the density functional method. The results indicate that Bi2O2Te is a narrow band gap semiconductor. The gap is formed by the Te 5p orbital at the top of the valence band and the Bi 6p orbital at the bottom of the conduction band. There are both ionic and covalent interactions within the Bi–O layers, and these layers are linked by the ionic Bi–Te bonds forming the crystal. Bi2O2Te is mechanically stable but anisotropic. It is easy to fracture along the c axis under shear stress. Its shear modulus is far smaller than its bulk modulus, so shape deformation is easier to occur than pure volume change. Its melting point is predicted to be 1284.0 K based on an empirical formula. The calculated refractive index at zero frequency reveals that Bi2O2Te is a negative uniaxial crystal with a birefringence of 0.51, making it a potential tuning material for optical application. The characteristics and origins of other optical properties are also discussed.

scholarly journals Structural, Electronic and Optical Properties of Cubic Perovskite Cspbx3 (X= Br, Cl and I)

2020 ◽  
Vol 8 (1) ◽  
pp. 23-28
Author(s):  
Aawzad A. Abdulkareem ◽  
Sarkawt A. Sami ◽  
Badal H. Elias
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Structural Parameters ◽  
Plane Waves ◽  
Experimental Studies ◽  
Visible Region ◽  
Electromagnetic Spectrum ◽  
Generalized Gradient ◽  
Electronic And Optical Properties ◽  
Low Energies

Plane waves with norm conserving pseudopotentials (PW-PP) method in conjunction with density functional theory (DFT) frame work have been used to investigate structural, electronic and optical properties of lead-halide cubic perovskite CsPbX3 (X=Br, Cl and I). The generalized gradient approximation (GGA), specifically Perdew-Burke-Ernzerhof (PBE) flavor, has been chosen to treat the exchange correlation term of Kohn-Sham equation. Structural parameters are comparable with other theoretical and experimental studies. In spite of good agreement of our band gap values  with other theoretical works, however, they were not comparable when compared to the experimental  values due to the well-known problem of Eg value underestimation of DFT. To update the  value, we have used GW method as a self-consistent quasiparticle method on energies and wave functions and indeed they have been improved. Optical properties have been calculated using density functional perturbation theory (DFPT). Our results show that CsPbX3 (X=Br, Cl, I) has maximum response to the electromagnetic spectrum at low energies (visible region) but minimum response at high energies.

Sign in / Sign up

Export Citation Format

Share Document