scholarly journals Effect of Pressure on Electronic and Optical Properties of SrAl2O4

2022 ◽  
Author(s):  
Hua Liang
Keyword(s):  
Optical Properties ◽  
Plane Waves ◽  
Theoretical Data ◽  
Blue Shift ◽  
Generalized Gradient ◽  
Electronic And Optical Properties ◽  
Effect Of Pressure ◽  
Optical Applications ◽  
Indirect Band Gap ◽  
Pseudo Potential

Abstract The effect of pressure on the electronic and optical properties of SrAl2O4 up to 25 GPa was studied by means of the pseudo-potential plane waves method within the generalized gradient approximation for exchange and correlation. The calculated lattice parameters are consistent with available experimental and theoretical data. By analyzing the electronic and optical properties, the pressure dependences of the electronic structures and optical constants were investigated. The band structures show an indirect band gap for this compound and the calculated band gaps expend with increasing pressure. Meanwhile, the optical properties including the dielectric spectra, absorption coefficient spectra, reflectivity, and the real part of the refractive index spectra in the low energy range have a blue shift. Given this, the optical properties of SrAl2O4 could be tuned by changing pressure to some degree, which is beneficial to the optical applications.

scholarly journals Structural, Optical, and Magnetic Properties of Gd Doped CdTe Quantum Dots for Magnetic Imaging Applications

2022 ◽  
Author(s):  
Shanmugapriya V ◽  
Bharathi S ◽  
Esakkinaveen D ◽  
Arunpandiyan S ◽  
Selvakumar B ◽  
...  
Keyword(s):  
Optical Properties ◽  
Plane Waves ◽  
Theoretical Data ◽  
Blue Shift ◽  
Generalized Gradient ◽  
Electronic And Optical Properties ◽  
Magnetic Imaging ◽  
Optical Applications ◽  
Indirect Band Gap ◽  
Pseudo Potential

Abstract The effect of pressure on the electronic and optical properties of SrAl2O4 up to 25 GPa was studied by means of the pseudo-potential plane waves method within the generalized gradient approximation for exchange and correlation. The calculated lattice parameters are consistent with available experimental and theoretical data. By analyzing the electronic and optical properties, the pressure dependences of the electronic structures and optical constants were investigated. The band structures show an indirect band gap for this compound and the calculated band gaps expend with increasing pressure. Meanwhile, the optical properties including the dielectric spectra, absorption coefficient spectra, reflectivity, and the real part of the refractive index spectra in the low energy range have a blue shift. Given this, the optical properties of SrAl2O4 could be tuned by changing pressure to some degree, which is beneficial to the optical applications.

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.

Band gap modulation effect on electronic and optical properties in PbTiO3 under stress: a DFT study

2019 ◽  
Vol 88 (1) ◽  
pp. 10501 ◽  
Author(s):  
Muhammad Rizwan ◽  
Rabia Bibi ◽  
Tariq Mahmood ◽  
Imran Aslam ◽  
Syed Sajid Ali Gillani ◽  
...  
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Blue Shift ◽  
First Principles Calculation ◽  
Generalized Gradient ◽  
Absorption Energy ◽  
Valence States ◽  
External Pressures ◽  
Band Gap Modulation ◽  
Pseudo Potential

First principles calculation was implemented to explore the effect of band gap modulation under stress in cubic PbTiO3 by using generalized gradient approximation (GGA) and ultrasoft pseudo-potential (USP). The band gaps at different external pressures show indirect band nature with significant reduction in band gapes. The density of states indicated that the upper valence states were influenced by O-2p and in the meantime Ti-d states have main contribution in conduction band. The inclusion of external stress not only changes electronic structure but also significantly changes the optical properties such as complex dielectric function, absorption, energy loss function, refractive index and reflectivity. The shifting of absorption edges toward higher energies confirm the presence of blue shift and make this material an appealing candidate for optoelectronic devices.

Topological band order, structural, electronic and optical properties of XPdBi (X = Lu, Sc) compounds

2016 ◽  
Vol 30 (14) ◽  
pp. 1650159 ◽  
Author(s):  
M. Narimani ◽  
Z. Nourbakhsh
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Local Density ◽  
Generalized Gradient ◽  
Linear Coefficient ◽  
Electronic And Optical Properties ◽  
Effect Of Pressure ◽  
The Density Functional Theory ◽  
Band Inversion ◽  
Inversion Strength

In this paper, the structural, electronic and optical properties of LuPdBi and ScPdBi compounds are investigated using the density functional theory by WIEN2K package within the generalized gradient approximation, local density approximation, Engel–Vosco generalized gradient approximations and modified Becke–Johnson potential approaches. The topological phases and band orders of these compounds are studied. The effect of pressure on band inversion strength, electron density of states and the linear coefficient of the electronic specific heat of these compounds is investigated. Furthermore, the effect of pressure on real and imaginary parts of dielectric function, absorption and reflectivity coefficients of these compounds is studied.

Electronic and Optical Properties of the Zn and Mg Doped AlN

2010 ◽  
Vol 663-665 ◽  
pp. 195-198 ◽  
Author(s):  
Xue Mei Cai ◽  
Yuan Luo
Keyword(s):  
Optical Properties ◽  
Imaginary Part ◽  
Density Functional ◽  
Absorption Peak ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Electronic And Optical Properties ◽  
The Density Functional Theory ◽  
Pseudo Potential ◽  
Mg Doped

The electronic and optical properties of hexagonal wurtzite AlN doped with Zn and Mg are studied based on the density functional theory. The density of states, dielectric function and absorption spectra are calculated using plane-wave ultrasoft pseudo-potential and the generalized gradient approximation (GGA). The absorption peaks are found during 0-13 eV and 43-48 eV in Mg doped AlN, while in Zn doped AlN, only during 0-15eV. The absorption peak about 43-48 eV found in Mg doped AlN is due to the transition of the deep 2p energy level in Mg to conduction band. The first peak of the dielectric imaginary part is related to the transition of the doped atoms. The peak of the dielectric imaginary part and absorption peak appears about 8 eV is due to the transition of N 2p to Al 3p state. Results show that the electronic and the optical properties of hexagonal wurtzite AlN are directly related to the electronic structure of the impurities in the crystal.

scholarly journals First principles calculations on the electronic and optical properties of zincblende BxGa1-xAs , and BxIn1-xAs semiconductor alloys.

2017 ◽  
pp. 5041-5048 ◽  
Author(s):  
N. Amrane ◽  
Maamar Benkraouda
Keyword(s):  
Optical Properties ◽  
Theoretical Data ◽  
Lattice Parameter ◽  
Interaction Matrix ◽  
Full Potential ◽  
Semiconductor Alloys ◽  
Generalized Gradient ◽  
Electronic And Optical Properties ◽  
Plane Wave Method ◽  
Linearized Augmented Plane Wave

A theoretical study of the electronic and optical properties of zincblende BxGa1-xAs and BxIn1-xAs  semiconductor alloys is presented, using the full potential linearized augmented plane wave method. In this approach, the generalized gradient approximation was used for the exchange–correlation potential. Ground state properties such as lattice parameter and band structure are calculated as a function of the mole fraction. We have also analyzed the optical properties (refractive index, dielectric function, real and imaginary), the 4x4 Kane’s interaction matrix is calculated in order to ease simulations of optoelectronic devices. The results have been discussed in terms of previously existing experimental and theoretical data, and comparisons with similar compounds have been made.

First-Principles Study of Structural, Electronic and Optical Properties in BaTi0.5Ni0.5O3

2013 ◽  
Vol 834-836 ◽  
pp. 268-271
Author(s):  
Hong Liang Pan ◽  
Shi Liang Yang ◽  
Teng Li
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Absorption Spectrum ◽  
First Principles ◽  
Energy Band Structure ◽  
Generalized Gradient ◽  
Electronic And Optical Properties ◽  
Generalized Gradient Approximation ◽  
Structure Density ◽  
Pseudo Potential

The pseudo-potential plane wave (PP-PW) mehod with the generalized gradient approximation (GGA) is applied to study the electronic and optical properties of BaTi0.5Ni0.5O3. The energy band structure, density of states (DOS) are obtained. The optical properties including the dielectric function, reflectivity, absorption spectrum, extinction coefficient, energy-loss spectrum and refractive index are also calculated and analyzed in detail.

DFT-BASEDAB INITIOSTUDY OF THE ELECTRONIC AND OPTICAL PROPERTIES OF CESIUM BASED FLUORO-PEROVSKITECsMF3(M = CaANDSr)

2012 ◽  
Vol 26 (32) ◽  
pp. 1250199 ◽  
Author(s):  
M. HARMEL ◽  
H. KHACHAI ◽  
M. AMERI ◽  
R. KHENATA ◽  
N. BAKI ◽  
...  
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Local Density ◽  
Theoretical Data ◽  
Full Potential ◽  
Generalized Gradient ◽  
Electronic Band ◽  
Electronic And Optical Properties ◽  
Structure Density

Density functional theory (DFT) is performed to study the structural, electronic and optical properties of cubic fluoroperovskite AMF3( A = Cs ; M = Ca and Sr ) compounds. The calculations are based on the total-energy calculations within the full-potential linearized augmented plane wave (FP-LAPW) method. The exchange-correlation potential is treated by local density approximation (LDA) and generalized gradient approximation (GGA). The structural properties, including lattice constants, bulk modulus and their pressure derivatives are in very good agreement with the available experimental and theoretical data. The calculations of the electronic band structure, density of states and charge density reveal that compounds are both ionic insulators. The optical properties (namely: the real and the imaginary parts of the dielectric function ε(ω), the refractive index n(ω) and the extinction coefficient k(ω)) were calculated for radiation up to 40.0 eV.

Monoelemental two-dimensional iodinene nanosheets: a first-principles study of the electronic and optical properties

2021 ◽  
Author(s):  
Asadollah Bafekry ◽  
C. Stampfl ◽  
M. Faraji ◽  
Bohayra Mortazavi ◽  
Mohamed Fadlallah ◽  
...  
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Blue Shift ◽  
Two Dimensional ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Electronic And Optical Properties ◽  
Exchange Correlation ◽  
Wide Range ◽  
First Time

Abstract Very recently, two-dimensional (2D) iodinene, a novel layered and buckled structure has been successfully fabricated [Mengmeng Qian et al., Adv. Mater. (2020) 2004835]. Motivated by this latest experimental accomplishment, for the first time we conduct density functional theory, firstprinciples calculations to explore the structural, electronic, and optical properties of monolayer, few-layer and bulk iodinene. Unlike the majority of monoelemental 2D lattices, iodinene is predicted to be an intrinsic semiconductor. On the basis of calculations using the generalized gradient approximation (GGA) of Perdew-Burke-Ernzerhof (PBE) for the exchange-correlation functional and the Heyd-Scuseria-Ernzerhof (HSE06) functional, it is shown that the electronic bandgap of iodinene decreases with increasing the number of atomic layers. Our HSE06 results reveal that the bandgap of iodinene decreases from 2.08 to 1.28 eV as the number of atomic layers change from one to five, highlighting the finely tunable bandgap. The optical study shows the monolayer has the ability to absorb a wide range of ultraviolet light, more than multilayers and bulk iodinene. As the number of layers increases, the absorption spectra exhibits a blue shift relative to monolayer iodinene. This study confirms the remarkable prospect for the application of iodinene in nanoelectronics and optoelectronics owing to its intrinsic semiconducting nature.

First principles and Debye model study of the thermodynamic, electronic and optical properties of MgO under high-temperature and pressure

2018 ◽  
Vol 32 (05) ◽  
pp. 1850047
Author(s):  
Yurun Miao ◽  
Huayang Li ◽  
Hongjuan Wang ◽  
Kaihua He ◽  
Qingbo Wang
Keyword(s):  
Optical Properties ◽  
Thermodynamic Properties ◽  
First Principles ◽  
Local Density ◽  
Blue Shift ◽  
Debye Model ◽  
Hybrid Functional ◽  
Generalized Gradient ◽  
Electronic And Optical Properties ◽  
Geological Processes

First principles and quasi-harmonic Debye model have been used to study the thermodynamic properties, enthalpies, electronic and optical properties of MgO up to the core–mantle boundary (CMB) condition (137 GPa and 3700 K). Thermodynamic properties calculation includes thermal expansion coefficient and capacity, which have been studied up to the CMB pressure (137 GPa) and temperature (3700 K) by the Debye model with generalized gradient approximation (GGA) and local-density approximation (LDA). First principles with hybrid functional method (PBE0) has been used to calculate the electronic and optical properties under pressure up to 137 GPa and 0 K. Our results show the Debye model with LDA and first principles with PBE0 can provide accurate thermodynamic properties, enthalpies, electronic and optical properties. Calculated enthalpies show that MgO keep NaCl (B1) structure up to 137 GPa. And MgO is a direct bandgap insulator with a 7.23 eV calculated bandgap. The bandgap increased with increasing pressure, which will induce a blue shift of optical properties. We also calculated the density of states (DOS) and discussed the relation between DOS and band, optical properties. Equations were used to fit the relations between pressure and bandgaps, absorption coefficient ([Formula: see text]([Formula: see text])) of MgO. The equations can be used to evaluate pressure after careful calibration. Our calculations can not only be used to identify some geological processes, but also offer a reference to the applications of MgO in the future.

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