Investigations of the Optical Properties of LaNi5 and LaNi4.5Sn0.5

2013 ◽  
Vol 321-324 ◽  
pp. 495-498 ◽  
Author(s):  
Dong Chen ◽  
Chao Xu
Keyword(s):  
Experimental Data ◽  
Refractive Index ◽  
Optical Properties ◽  
Density Functional ◽  
Low Frequency ◽  
Potential Method ◽  
Frequency Region ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Pseudo Potential

The reflectivity, loss function, refractive index, extinction coefficient and dielectric function of the LaNi5and LaNi4.5Sn0.5intermetallic compounds are investigated through the plane-wave pseudo-potential method based on the density functional theory. The effects of Sn impurity are discussed and some interesting features are found in the low frequency region. Some important optical properties such as static dielectric constant and static refractive index are obtained. The equation [n (0)]2=ε1(0)is satisfied according to our calculation, which indicates that our results are correct and reasonable. Nevertheless, the calculated results need to be testified in the future due to the lack of experimental data.

High-Pressure Electronic and Optical Properties of α-Si3N4

2011 ◽  
Vol 415-417 ◽  
pp. 2288-2291
Author(s):  
Chang Chun Chen ◽  
Xiao Ju Geng ◽  
Ying Bin Li ◽  
Ben Hai Yu ◽  
Dong Chen
Keyword(s):  
Experimental Data ◽  
Dielectric Function ◽  
Density Functional ◽  
Potential Method ◽  
Band Structure Calculation ◽  
Functional Theory ◽  
Lattice Constants ◽  
The Density Functional Theory ◽  
The Stability ◽  
Pseudo Potential

Based on the density functional theory, the plane-wave pseudo-potential method is performed to investigate the structural properties of α-Si3N4. The ground-state lattice parameters (i.e. lattice constants and cell volume) agree quite well with the experimental data. From the band structure calculation, we found that the stability of α-Si3N4is due mainly to the interaction among the Si-s, Si-p and N-p states. The imaginary part of the dielectric function has a sharp peak at 8.2eV. For the real part of the dielectric function, the highest peak locates at 6.5eV. Our calculated results are in good agreement with the experimental data and previous theoretical values. Therefore, the calculated results may provide useful information for further investigations of α-Si3N4.

Electronic Structure and Optical Properties of InN: A First-Principles Study

2013 ◽  
Vol 760-762 ◽  
pp. 425-428
Author(s):  
Wei Hua Wang ◽  
Guo Zhong Zhao
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Density Functional ◽  
Potential Method ◽  
First Principles Calculations ◽  
Generalized Gradient ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Structure Density ◽  
Pseudo Potential

The electronic properties and the optical properties of wurtzite InN are studied by the first-principles calculations based on the density functional theory. The calculations are based on the Generalized-Gradient Approximation (GGA) and implemented in Plane Wave Self-Consist Field (PWSCF). The optical properties of InN are investigated by the pseudo-potential method with PBEsol-GGA within the WIEN2K program. Band structure, density of states and dielectric functions are calculated detailedly. The energy transitions are observed and compared existing data at critical points. Moreover the new peak in between the region 12 eV to 14 eV should be due to transitions from the In-5p states to the N-2s states.

Study on Electronic Structure of GaN under Pressure

2014 ◽  
Vol 900 ◽  
pp. 217-221
Author(s):  
Xing Xiang Ruan ◽  
Xian Hui Zhong ◽  
Fu Chun Zhang ◽  
Wei Hu Zhang
Keyword(s):  
Electronic Structure ◽  
Density Functional ◽  
Energy Gap ◽  
Potential Method ◽  
High Energy ◽  
Functional Theory ◽  
Conduction Bands ◽  
The Density Functional Theory ◽  
The Relationship ◽  
Pseudo Potential

A detailed theoretical study of electronic structure and optical properties of GaN under pressure was performed by the first-principles calculations of plane wave ultra-soft pseudo-potential method based on the density functional theory (DFT). The results indicate that Ga-N bond length becomes shorter and the valence bonds shift towards the low energy while the conduction bands towards high energy, the band gap becomes wider with the pressure increasing, and theoretical studies explained the relationship between the band edges, energy gap of GaN and pressure. In addition, the peak in band was cracked slightly, and the Ga 3d-N 2p hybridization was enhanced.

Computer Simulation of the Magnesium Silicide Polymorphs

2012 ◽  
Vol 170-173 ◽  
pp. 3312-3315
Author(s):  
Dong Chen ◽  
Chao Xu
Keyword(s):  
Optical Properties ◽  
Energy Region ◽  
High Performance ◽  
Density Functional ◽  
High Energy ◽  
Magnesium Silicide ◽  
High Energy Region ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Pseudo Potential

The anti-cotunnite magnesium silicide was constructed, and its absorption coefficient, dielectric function and loss function have been investigated through the plane-wave pseudo- potential calculations based on the density functional theory. In our scheme, we consider the Mg2Si crystal without defects or cracks. Significant features have been observed for the optical properties in the low-energy region and the high-energy region. The main focus of this paper is to determine the high-pressure optical properties of Mg2Si and find out if this material can be used as high-performance thermoelectric devices.

First-principles study on electronic structure and optical properties of In-doped GaN

2014 ◽  
Vol 13 (08) ◽  
pp. 1450070 ◽  
Author(s):  
Xingxiang Ruan ◽  
Fuchun Zhang ◽  
Weihu Zhang
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
First Principles ◽  
Density Functional ◽  
Visible Region ◽  
Solar Spectrum ◽  
Potential Method ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Structure Density

The In -doped GaN is investigated by first-principles calculations of plane wave ultra-soft pseudo-potential method based on the density functional theory (DFT). The band structure, electronic structure, density of states and optical properties are investigated. The results indicate that the band-gap becomes narrower and the absorption edge of optical properties is red-shifted with the increase in In -doped concentration. Meanwhile, the visible region has strong absorption properties, and the significant absorption peaks are observed near 3.0 eV and 6.1 eV. The other peaks correspond to the wavelength of absorption spectra from the ultraviolet portion extending to the infrared portion, which almost covers the entire solar spectrum. The studied results show that In -doped GaN can be applied as solar cell and transparent conductivity material.

DENSITY-FUNCTIONAL STUDY OF THE SURFACE AND INTERFACE OF ZnO/α-Al2O3(0001)

2004 ◽  
Vol 11 (06) ◽  
pp. 509-513 ◽  
Author(s):  
CHUN YANG ◽  
YAN-RONG LI ◽  
JIN-SAN LI ◽  
WEI-FEI YU
Keyword(s):  
Density Functional ◽  
Atomic Layer ◽  
Potential Method ◽  
Interface Structure ◽  
Functional Study ◽  
Functional Theory ◽  
Surface And Interface ◽  
The Density Functional Theory ◽  
Α Al2o3 ◽  
Pseudo Potential

α- Al 2 O 3(0001), [Formula: see text] surface and ZnO /α- Al 2 O 3(0001) interface are theoretically studied by using a plane wave ultrasoft pseudo-potential method based on the density functional theory. The larger relaxing occurs at the top Al - O layer on α- Al 2 O 3(0001) surface. We have found that greater amounts of charge transfer occur on the [0001] Zn surface than in the case of the [Formula: see text] surface, and that the O -terminated surface of ZnO is more stable. We have also demonstrated that ZnO thin films growth on α- Al 2 O 3(0001) has the orientation of [Formula: see text] with the interface structure of the (substrate)- Al - Zn - O - Zn - O atomic layer, and also the O -terminated surface.

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.

Phase Structures and Properties of Au-Pd-M (M=Zr, Mo, Y) System

2015 ◽  
Vol 816 ◽  
pp. 722-725
Author(s):  
Ming Xie ◽  
You Cai Yang ◽  
Ji Ming Zhang ◽  
Yong Tai Chen ◽  
Sai Bei Wang ◽  
...  
Keyword(s):  
First Principles ◽  
Electronic Structures ◽  
Density Functional ◽  
Solidification Rate ◽  
Potential Method ◽  
Functional Theory ◽  
Structures And Properties ◽  
The Density Functional Theory ◽  
Calculation Results ◽  
Pseudo Potential

A series of new alloys including Au-Pd-M (M=Zr, Mo, Y) were developed in this study. The physical properties, electrical properties parameters and thermodynamics database of the alloys were established. The phase structure and composition were analyzed. The calculation results were verified by experiments. The influence of solidification rate to microstructures, morphology and grain size of Au-Pd-M alloys were analyzed. A first-principles plane-wave pseudo-potential method based on the density functional theory was used to investigate the electronic structures, bonding characters and energetic stability of Au-Pd-M alloys, the calculating results indicated that Au-Pd-Mo formed more easily than Au-Pd-Zr and Au-Pd-Y, and the formed Au-Pd-Mo is more stable than Au-Pd-Zr and Au-Pd-Y.

scholarly journals FIRST-PRINCIPLES STUDY OF THE EFFECTS OF GOLD ADSORPTION ON THE Al(001) SURFACE PROPERTIES

2008 ◽  
Vol 19 (10) ◽  
pp. 1563-1579 ◽  
Author(s):  
N. ZARE DEHNAVI ◽  
M. PAYAMI
Keyword(s):  
Dipole Moment ◽  
Work Function ◽  
Density Functional ◽  
Potential Method ◽  
Ionic Charge ◽  
Functional Theory ◽  
Adsorption Sites ◽  
The Density Functional Theory ◽  
Surface Dipole ◽  
Pseudo Potential

In this paper, we have studied theoretically the effects of gold adsorption on the Al (001) surface, using ab initio pseudo-potential method in the framework of the density functional theory. Having found the hollow sites at the Al (001) surface as the most preferred adsorption sites, we have investigated the effects of the Au adsorption with different coverages (Θ =0.11, 0.25, 0.50, 0.75, 1.00 ML) on the geometry, adsorption energy, surface dipole moment, and the work function of the Al (001) surface. The results show that even though the work function of the Au substrate increases with the Au coverage, the surface dipole moment decreases with the changes in coverage from Θ =0.11 to 0.25 ML. We have explained this behavior by analyzing the electronic and ionic charge distributions. Furthermore, by studying the diffusion of Au atoms into the substrate, we have shown that at room temperature the diffusion rate of Au atoms into the substrate is negligible but increasing the temperature to about 200°C the Au atoms significantly diffuse into the substrate, in agreement with the experiment.

Effect of Ti incorporation on the electronic structure and optical properties of MoS2 (a first principle study)

2021 ◽  
Author(s):  
Perveen Akhtar ◽  
M. Junaid Iqbal Khan
Keyword(s):  
Density Functional Theory ◽  
Dielectric Constant ◽  
Refractive Index ◽  
Optical Properties ◽  
Density Functional ◽  
First Principle ◽  
Photovoltaic Devices ◽  
Functional Theory ◽  
Electronic And Optical Properties ◽  
The Density Functional Theory

Abstract Current study contains the results of the structural, electronic, and optical properties of the Ti doped MoS2. We perform this research using the density functional theory where we employ PBE-GGA approximation in the Wien2k code. We substitute Mo atoms with Ti atoms and calculated structural, electronic, and optical properties. The results of PDOS and TDOS indicate that Ti 3d-states help in tuning the electronic properties. Optical absorption is blue shifted upon adding Ti contents to the host MoS2. An increase in refractive index and dielectric constant is observed. However, absorption and conductivity is improved for the 5.55% Ti concentration which points that Ti:MoS2 material may be used for fabrication of the optoelectronic, photonic, and photodetector and photovoltaic devices.

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