Effect of strain on the electronic structure and optical properties of germanium

2018 ◽  
Vol 32 (12) ◽  
pp. 1850140 ◽  
Author(s):  
Shumin Wen ◽  
Chunwang Zhao ◽  
Jijun Li ◽  
Qingyu Hou
Keyword(s):  
Dielectric Constant ◽  
Optical Properties ◽  
Optical Conductivity ◽  
Density Functional ◽  
Tensile Strain ◽  
Local Density ◽  
Compressive Strain ◽  
Static Dielectric Constant ◽  
Functional Theory ◽  
Screened Exchange

The effects of biaxial strain parallel to the (001) plane on the electronic structures and optical properties of Ge are calculated using the first-principles plane-wave pseudopotential method based on density functional theory. The screened-exchange local-density approximation function was used to obtain more reliable band structures, while strain was changed from −4% to [Formula: see text]4%. The results show that the bandgap of Ge decreases with the increase of strain. Ge becomes a direct-bandgap semiconductor when the tensile strain reaches to 2%, which is in good agreement with the experimental results. The density of electron states of strained Ge becomes more localized. The tensile strain can increase the static dielectric constant distinctly, whereas the compressive strain can decrease the static dielectric constant slightly. The strain makes the absorption band edge move toward low energy. Both the tensile strain and compressive strain can significantly increase the reflectivity in the range from 7 eV to 14 eV. The tensile strain can decrease the optical conductivity, but the compressive strain can increase the optical conductivity significantly.

scholarly journals Strain Induced Electronic and Optical Properties of 2D Silicon Carbide Monolayer Using Density Functional Theory

2021 ◽  
Vol 7 (1) ◽  
pp. 60-65
Author(s):  
S. B. Sharma ◽  
R. Adhikari ◽  
K. R. Sigdel ◽  
R. Bhatta
Keyword(s):  
Silicon Carbide ◽  
Dielectric Constant ◽  
Refractive Index ◽  
Optical Properties ◽  
Density Functional ◽  
Compressive Strain ◽  
Static Dielectric Constant ◽  
Functional Theory ◽  
First Principle Calculation ◽  
Electronic And Optical Properties

Using the first principle calculation, we investigated the structural, electronic, and strain-dependent optical properties of the two-dimensional hexagonal Silicon Carbide (SiC) Monolayer. We found that the biaxial compressive strain loading gradually changes the direct bandgap SiC into indirect bandgap semiconductor. The compressive strain increases the bandgap but reduces the values of static dielectric constant and refractive index. Conversely, the biaxial tensile strain loading decreases the bandgap but increases the value of static dielectric constant and refractive index. The result shows that the electronic and optical properties of SiC can be engineered to the desired value by applying strain. The large bandgap issue for the SiC monolayer is limiting its uses in different applications which can be overcome with the help of biaxial strain.

Ab initio study of oxygen vacancy effects on electronic and optical properties of NiO

MRS Advances ◽  
2016 ◽  
Vol 1 (37) ◽  
pp. 2617-2622 ◽  
Author(s):  
John Petersen ◽  
Fidele Twagirayezu ◽  
Pablo D. Borges ◽  
Luisa Scolfaro ◽  
Wilhelmus Geerts
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Local Density ◽  
Optical Transition ◽  
Energy Levels ◽  
Density Functional Theory Calculations ◽  
Local Density Of States ◽  
Functional Theory ◽  
Electronic And Optical Properties ◽  
O Vacancy

ABSTRACTDensity Functional Theory calculations of electronic and optical properties of NiO, with and without O vacancies, are the focus of this work. Two bands, one fully occupied and the other unoccupied, induced by an O vacancy, are found in the gap. These energy levels are identified and analyzed by means of a local density of states (LDOS) calculation, and notable crystal field splitting can be seen. The real and imaginary parts of the dielectric function are calculated, and an additional optical transition can be seen at lower energy, which can be attributed to the O vacancy induced state in the band gap.

First-principles study of the stability of silicane and germanane under strain

2014 ◽  
Vol 28 (17) ◽  
pp. 1450138 ◽  
Author(s):  
T. Y. Du ◽  
J. Zhao ◽  
G. Liu ◽  
J. X. Le ◽  
B. Xu
Keyword(s):  
First Principles ◽  
Lattice Dynamics ◽  
Density Functional ◽  
Tensile Strain ◽  
Helmholtz Free Energy ◽  
Compressive Strain ◽  
Specific Capacity ◽  
Biaxial Strain ◽  
Functional Theory ◽  
The Stability

In this paper, we investigate the structural stability of silicane and germanane under biaxial strain by employing the lattice dynamics calculations within the frame of density functional theory. Our results show that silicane and germanane become unstable even under 1% compressive strain, while maintaining stable under tensile strain. Further calculations about the thermodynamical properties of silicane and germanane show that the phonon contribution to Helmholtz free energy, entropy and specific capacity are insensitive to the tensile strain.

scholarly journals Structure, electronic and optical properties of chalcopyrite-type nano-clusters XFeY2 (X=Cu, Ag, Au; Y=S, Se, Te): a density functional theory study

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Prabhat Ranjan ◽  
Praveen K. Surolia ◽  
Tanmoy Chakraborty
Keyword(s):  
Density Functional Theory ◽  
Dielectric Constant ◽  
Refractive Index ◽  
Optical Properties ◽  
Solar Cells ◽  
Density Functional ◽  
Energy Gap ◽  
Lumo Energy ◽  
Functional Theory ◽  
Homo Lumo

Abstract Iron-based chalcopyrite materials have diverse applications in solar cells, spintronic, thermoelectric devices, LEDs and medical sciences. In this report we have studied structure, electronic and optical properties of chalcopyrite-type nano-cluster XFeY2 (X=Cu, Ag, Au; Y=S, Se, Te) systematically by using Density Functional Theory (DFT). Our computed HOMO-LUMO energy gap of XFeY2 is in the range of 1.568–3.982 eV, which endorses its potential application in optoelectronic devices and solar cells. The result shows that chalcopyrite-type material AuFeS2 having a star-type structure with point group C2v and sextet spin multiplicity, is the most stable cluster with HOMO-LUMO energy gap of 3.982 eV. The optical properties viz. optical electronegativity, refractive index, dielectric constant, IR and Raman activity of these nano-clusters are also investigated. The result exhibits that HOMO-LUMO energy gap of XFeY2 along with optical electronegativity and vibrational frequency decreases from S to Se to Te, whereas refractive index and dielectric constant increases in the reverse order.

First-principles study of electronic and optical properties of solid-solution ZnO1−xSx

2017 ◽  
Vol 31 (23) ◽  
pp. 1750175 ◽  
Author(s):  
Margi Jani ◽  
Abhijit Ray
Keyword(s):  
Solid Solution ◽  
Density Functional Theory ◽  
Optical Properties ◽  
First Principles ◽  
Density Functional ◽  
Local Density ◽  
Density Approximation ◽  
Functional Theory ◽  
Electronic And Optical Properties ◽  
Strong Localization

We investigated the electronic and optical properties of ZnO under the circumstances of isovalent anionic doping by sulfur. A pseudopotential implementation of density functional theory is applied within the local density approximation to examine the modification of band structure in wurtzite ZnO by sulfur substitution. Although Fermi level position does not change, a strong localization of Zn-[Formula: see text] orbital is found by S-doping. Optical properties and constants are found to strongly depend on the sulfur content at low photon energies.

First-Principles Study of Electronic Structure, Optical Properties and LO-TO Splitting of GaP

2018 ◽  
Vol 787 ◽  
pp. 9-15
Author(s):  
Xian Bin Zhang ◽  
Wen Jie Wu ◽  
Ning Kang Deng ◽  
Xu Yan Wei ◽  
Guan Qi Wang
Keyword(s):  
Density Functional Theory ◽  
Dielectric Constant ◽  
Optical Properties ◽  
Electronic Structure ◽  
First Principles ◽  
Effective Charge ◽  
Density Functional ◽  
Optical Frequency ◽  
Generalized Gradients ◽  
Functional Theory

The electronic structure and optical properties of GaP were calculated using generalized gradients in density functional theory. The Bonn effective charge, optical frequency dielectric constant and the LO-TO splitting value were calculated by density functional theory perturbation method.

Modeling Optical Properties of Small Metallic Nanoparticles Based on Density Functional Theory

2007 ◽  
Author(s):  
Yi He ◽  
Taofang Zeng
Keyword(s):  
Optical Properties ◽  
Metallic Nanoparticles ◽  
Density Functional ◽  
Local Density ◽  
Incident Light ◽  
Tight Binding ◽  
Local Density Of States ◽  
Functional Theory ◽  
Hamilton Matrix ◽  
Different Diameters

Optical properties of silver nanoparticles with different diameters are investigated based on the electronic structures of component silver atoms. Within the frame of tight binding method, the local density of states of each silver atom is obtained through a recursive approach that extracts the required information directly from the Hamilton matrix. Then the interaction between the electric field of incident light and electrons in the nanoparticles is simulated to characterize their optical features and the size effects were interpreted according the results.

Study of Structural, Electronic and Optical Properties of Lanthanum Doped Perovskite PZT Using Density Functional Theory

2017 ◽  
Vol 864 ◽  
pp. 127-132 ◽  
Author(s):  
N.H. Hussin ◽  
Mohamad Fariz Mohamad Taib ◽  
Mohd Hazrie Samat ◽  
N. Jon ◽  
Oskar Hasdinor Hassan ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Refractive Index ◽  
Optical Properties ◽  
Density Functional ◽  
Local Density ◽  
Ferroelectric Materials ◽  
Good Prediction ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Electronic And Optical Properties

Ferroelectric materials of lanthanum (La) doped PbZrTiO3 (PLZT) were investigated via first principles study. The structural, electronic and optical properties of PLZT in tetragonal structure (P4mm space group) were performed in the framework of density functional theory (DFT) with generalized gradient approximation (GGA) and local density approximation (LDA) methods. The calculated results of structural properties of PLZT were seen to be approximately close to the experimental data. The results of the electronic part were covered with the calculation of energy band gap and density of states (DOS). The highest valence band (VB) which lies at the Fermi level (EF) was dominated by the O 2p at F point. The conduction band (CB) of PLZT occurred at G point, which was primarily dominated by Ti 3d mixed at Pb and La p-state. Whereas the optical part was covered with the refractive index and absorption. The refractive index, n and the extinction coefficient, k were calculated with respect to photon energy. Those results obtained could be such a good prediction in studying parameters and properties of new materials.

Monitoring the electronic, thermal and optical properties of two-dimensional MoO2 under strain via vibrational spectroscopies: a first-principles investigation

2019 ◽  
Vol 21 (36) ◽  
pp. 19904-19914 ◽  
Author(s):  
Fatih Ersan ◽  
Sevil Sarikurt
Keyword(s):  
Density Functional Theory ◽  
Optical Properties ◽  
First Principles ◽  
Density Functional ◽  
Tensile Strain ◽  
Two Dimensional ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Vibrational Spectroscopies

This study presents the electronic, mechanical, thermal, vibrational and optical properties of the MoO2 monolayer under the effect of biaxial and uniaxial compressive/tensile strain, using first-principles calculations based on density functional theory.

Sign in / Sign up

Export Citation Format

Share Document