First-Principles Study on Electronic and Thermal Properties of Zinc-Blende Metal Telluride

2011 ◽  
Vol 335-336 ◽  
pp. 1056-1060
Author(s):  
Dong Chen ◽  
Feng Peng
Keyword(s):  
Crystal Structure ◽  
Heat Capacity ◽  
Thermal Properties ◽  
Plane Wave ◽  
First Principles ◽  
Sharp Increase ◽  
Potential Method ◽  
Zinc Blende ◽  
Structure Density ◽  
Pseudo Potential

The equilibrium crystal structure, band structure, density of states, bulk modulus and its first pressure derivate of CdTe are systemically calculated by first-principles plane-wave pseudo-potential method, and then compared with experimental results. Applying the vibrational Debye-like model, complete sets of isochoric heat capacities can be obtained up to 1000K at pressure or not. With the temperature increasing from 0 to 1000K, a sharp increase in the heat capacity is observed. Moreover, the dependences between cell volume and pressure are also successfully obtained. Our calculated results are in agreement with available results.

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.

Ab Initio Study of Structural and Optical Properties of SrTi0.5Nb0.5O3

2013 ◽  
Vol 846-847 ◽  
pp. 1935-1938
Author(s):  
Hong Liang Pan ◽  
Teng Li ◽  
Shi Liang Yang ◽  
Yi Ming Liu
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
Plane Wave ◽  
First Principles ◽  
Ab Initio Study ◽  
Structural And Optical Properties ◽  
Metallic Behavior ◽  
Conduction Bands ◽  
Structure Density ◽  
Pseudo Potential

The electronic structure, including band structure, density of states ( DOS) and optical properties of SrTi0.5Nb0.5O3are calculated from the first principles of plane wave ultra soft pseudo potential technology. The calculated results reveal that due to the electron doping, the Fermi level moves into the conduction bands and the system shows metallic behavior. The optical properties are also discussed in detail.

Structural aspects of thermal properties of AgCuS compound

2020 ◽  
Vol 34 (05) ◽  
pp. 2050066 ◽  
Author(s):  
Y. I. Aliyev ◽  
Y. G. Asadov ◽  
T. M. Ilyasli ◽  
F. M. Mammadov ◽  
T. G. Naghiyev ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Heat Capacity ◽  
Thermal Properties ◽  
Central Peak ◽  
Orthorhombic Symmetry ◽  
Cubic Symmetry ◽  
Space Group ◽  
Temperature Ranges ◽  
Structural Aspects

The crystal structure and thermal properties of AgCuS compound were investigated at high temperature ranges. It was found that the crystal structure of these compounds has orthorhombic symmetry with Cmcm space group at the normal condition and room temperature. The phase transition to cubic symmetry with Fm3m space group is observed at [Formula: see text] temperature. The endoeffect was observed with a central peak at [Formula: see text] in the differential thermal analysis. The temperature dependence on heat capacity was obtained in the range of [Formula: see text] temperature. Thermodynamic parameters have been determined: enthalpy and heat capacity. The value of enthalpy was calculated according to the temperature of the phase transition.

The Effect of Cr Addition on the Microstructure of TiNi: First-Principles Calculations

2014 ◽  
Vol 881-883 ◽  
pp. 1351-1354
Author(s):  
Wei Bing Zhang ◽  
Kai Long ◽  
Xiao Cheng
Keyword(s):  
Binding Energy ◽  
Plane Wave ◽  
First Principles ◽  
Niti Alloy ◽  
Formation Enthalpy ◽  
Wave Method ◽  
First Principles Calculations ◽  
Plane Wave Method ◽  
Cr Addition ◽  
Pseudo Potential

Based on the first-principles pseudo-potential plane wave method, the effect of Cr addition on the microstructure of NiTi alloys are characterized and assessed with the formation enthalpy (ΔH), binding energy (ΔE) and density of states (DOS) distribution of NiTi (Cr) crystals. The results show that the binding energy of NiTi (CrNi) is slightly smaller than that of NiTi (CrTi), but the formation enthalpy of NiTi (CrTi) is much smaller than that of NiTi (CrNi).So the Ms of NiTi alloy could be decreased by the addition of ratio for Ni/Ti. And the electronic microstucture of NiTi (CrNi) alloy are also illustrated clearly.

Computer Simulation of the Metal Silicide

2012 ◽  
Vol 170-173 ◽  
pp. 3367-3370
Author(s):  
Dong Chen ◽  
Chao Xu
Keyword(s):  
Dielectric Constant ◽  
First Principles ◽  
Plasma Frequency ◽  
Low Frequency ◽  
Potential Method ◽  
Frequency Region ◽  
Optical Parameters ◽  
Metal Silicide ◽  
Near Future ◽  
Pseudo Potential

We have investigated the optical properties of the Fm-3m-Mg2Si using the first-principles plane-wave pseudo-potential method. Some important optical parameters (reflectivity, refractive index, extinction coefficient, loss function and dielectric function) are calculated and investigated at high pressure. The calculated static dielectric constant ε(0) is 15.9. The computed plasma frequency is 12eV. Some interesting features in the optical parameters are found in the low frequency region. Nevertheless, the calculated result needs to be testified by experiments in the near future.

Optical Properties of β-Si3N4 Studied from First-Principles Method

2012 ◽  
Vol 490-495 ◽  
pp. 3253-3256 ◽  
Author(s):  
Dong Chen ◽  
Kui Yang
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Theoretical Study ◽  
Potential Method ◽  
First Principles Calculations ◽  
Generalized Gradient ◽  
Generalized Gradient Approximation ◽  
Near Future ◽  
Pseudo Potential ◽  
Good Agreement

A detailed theoretical study of the optical properties of β-Si3N4 has been carried out by means of first-principles calculations using the plane-wave pseudo-potential method with generalized gradient approximation for the exchange and correlation functional. The calculated maximum absorption coefficient is 312000, which is in good agreement with the other calculated result. β-Si3N4 can be used as a photo-electronic material because its absorption curve has an abrupt limit at low energy region. The light beam with the frequency of 7eV～15eV can easily traverse the β-Si3N4 crystal. For the dielectric function, the strongest peaks are located at 6.5 and 9.0eV for the real and imaginary parts, respectively. Moreover, the calculated static dielectric constant is 3.21. Actually speaking, our calculated results should be testified by experiments in the near future.

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.

Thermodynamic Properties of Wurtzite and Zinc-Blende AlN

2013 ◽  
Vol 455 ◽  
pp. 127-130
Author(s):  
Xue Mei Cai ◽  
Jing Mei Wang ◽  
Qian Neng Zhou
Keyword(s):  
Free Energy ◽  
Thermodynamic Properties ◽  
Room Temperature ◽  
Potential Method ◽  
Zinc Blende ◽  
Phonon Spectra ◽  
The Difference ◽  
Increasing Temperature ◽  
Pseudo Potential ◽  
Good Agreement

In this paper, we carry out linear response calculation to determine the phonon density of states and the thermodynamic properties of the wurtzite and zinc-blende AlN by using the norm-conserving pseudo-potential method. The optimized lattice constant is in good agreement with the available experimental data. The internal energies increase almost linearly with temperature and the phonon free energy curves move down with increasing temperature in both structures. The zero value of the lattice vibration free energy appears at temperature 707K in wurtzite and 728K in zinc-blende AlN respectively. The specific heat capacity of the wurtzite AlN is higher than that of the zinc-blende AlN at room temperature owing to the difference of the phonon spectra.

scholarly journals Thermal response of electronic, optical, mechanical properties, phonon frequencies, and sound velocity of InPxAsySb1-x-y/InAs quaternary semiconductor system

2022 ◽  
Author(s):  
A R Degheidy ◽  
A M AbuAli ◽  
Elkenany B Elkenany
Keyword(s):  
Thermal Properties ◽  
Thermal Response ◽  
Quaternary Alloy ◽  
Potential Method ◽  
Effect Of Temperature ◽  
Virtual Crystal Approximation ◽  
Semiconductor System ◽  
Acoustic Velocities ◽  
Experimental Values ◽  
Pseudo Potential

Abstract The temperature dependence of acoustic velocities, thermal properties, and phonon frequencies, mechanical, electronic, and optical properties for the InPxAsySb1-x-y/InAs system has been studied. The physical properties of the binary components InSb, InP, and InAs that constitute the quaternary alloy were used in this research. The study has been done using the empirical pseudo-potential method (EPM) under the virtual crystal approximation (VCA). The thermal properties, phonon frequencies, and acoustic velocities for the InPxAsySb1-x-y/InAs system under the effect of temperature have not been fully studied. Therefore, we have focused on these properties under the influence of temperature. Due to the lack of the published theoretical and experimental values on these properties, our findings will provide a significant reference for future experimental work.

Structural and thermal properties of the monoclinic Lu2SiO5single crystal: evaluation as a new laser matrix

2009 ◽  
Vol 42 (2) ◽  
pp. 284-294 ◽  
Author(s):  
Hengjiang Cong ◽  
Huaijin Zhang ◽  
Jiyang Wang ◽  
Wentao Yu ◽  
Jiandong Fan ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Thermal Conductivity ◽  
Heat Capacity ◽  
Thermal Expansion ◽  
Thermal Properties ◽  
Specific Heat ◽  
Linear Thermal Expansion ◽  
Cell Parameters ◽  
Thermal Expansion Tensor ◽  
Anisotropic Thermal Conductivity

The crystal structure of monoclinic Lu2SiO5(LSO) crystals, grown by the Czochralski method, was determined at room temperature by X-ray diffraction. The unit-cell parameters area= 10.2550 (2),b= 6.6465 (2),c= 12.3626 (4) Å, β = 102.422 (1)° in space groupI2/a. The linear thermal expansion tensor was determined along thea,b,candc* directions over the temperature range from 303.15 to 768.15 K, and the principal coefficients of the thermal expansion tensor are found to be αI= −1.0235 × 10−6 K, αII= 4.9119 × 10−6 K and αIII= 10.1105 × 10−6 K. The temperature dependence of the cell volume and monoclinic angle were also evaluated. In addition, the specific heat and the thermal diffusivity were measured over the temperature ranges from 293.15 to 673.15 K and from 303.15 to 572.45 K, respectively. As a result, the anisotropic thermal conductivity could be calculated and is reported for the first time, to the best of the authors' knowledge. The specific heat capacity of LSO is 139.54 J mol−1 K−1, and the principal components of the thermal conductivity arekI= 2.26 W m−1 K−1,kII= 3.14 W m−1 K−1andkII= 3.67 W m−1 K−1at 303.15 K. A new structure model was proposed to better understand the relationships between the crystal structure and anisotropic thermal properties. In comparison with other laser matrix crystals, it is found that LSO possesses relatively large anisotropic thermal properties, and owing to its small heat capacity it has a moderate thermal conductivity, which is similar to those of the tungstates but lower than those of the vanadates.

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