Ab Initio Calculation of the Electronic Band Structure, Density of States and Optical Properties of α-2-Methyl-1-nitroisothiourea

2009 ◽  
Vol 113 (38) ◽  
pp. 12648-12654 ◽  
Author(s):  
Ali Hussain Reshak ◽  
Dalibor Stys ◽  
S. Auluck ◽  
I. V. Kityk
Keyword(s):  
Optical Properties ◽  
Band Structure ◽  
Ab Initio ◽  
Density Of States ◽  
Ab Initio Calculation ◽  
Electronic Band Structure ◽  
Electronic Band ◽  
Structure Density

scholarly journals An ab-initio study on structural, elastic, electronic, bonding, thermal, and optical properties of topological Weyl semimetal TaX (X = P, As)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. I. Naher ◽  
S. H. Naqib
Keyword(s):  
Optical Properties ◽  
Band Structure ◽  
Fermi Level ◽  
Density Of States ◽  
Electronic Band Structure ◽  
Optical Parameters ◽  
Electronic Density ◽  
Electronic Band ◽  
Wide Range ◽  
Weyl Semimetals

AbstractIn recent days, study of topological Weyl semimetals have become an active branch of physics and materials science because they led to realization of the Weyl fermions and exhibited protected Fermi arc surface states. Therefore, topological Weyl semimetals TaX (X = P, As) are important electronic systems to investigate both from the point of view of fundamental physics and potential applications. In this work, we have studied the structural, elastic, mechanical, electronic, bonding, acoustic, thermal and optical properties of TaX (X = P, As) in detail via first-principles method using the density functional theory. A comprehensive study of elastic constants and moduli shows that both TaP and TaAs possesses low to medium level of elastic anisotropy (depending on the measure), reasonably good machinability, mixed bonding characteristics with ionic and covalent contributions, brittle nature and relatively high Vickers hardness with a low Debye temperature and melting temperature. The minimum thermal conductivities and anisotropies of TaX (X = P, As) are calculated. Bond population analysis supports the bonding nature as predicted by the elastic parameters. The bulk electronic band structure calculations reveal clear semi-metallic features with quasi-linear energy dispersions in certain sections of the Brillouin zone near the Fermi level. A pseudogap in the electronic energy density of states at the Fermi level separating the bonding and the antibonding states indicates significant electronic stability of tetragonal TaX (X = P, As).The reflectivity spectra show almost non-selective behavior over a wide range of photon energy encompassing visible to mid-ultraviolet regions. High reflectivity over wide spectral range makes TaX suitable as reflecting coating. TaX (X = P, As) are very efficient absorber of ultraviolet radiation. Both the compounds are moderately optically anisotropic owing to the anisotropic nature of the electronic band structure. The refractive indices are very high in the infrared to visible range. All the energy dependent optical parameters show metallic features and are in complete accord with the underlying bulk electronic density of states calculations.

scholarly journals Ab-initio Calculation Study of Electronic Band Structure of CdTe with Low-index Surface

2021 ◽  
Vol 13 (3) ◽  
pp. 03041-1-03041-5
Author(s):  
O. M. Chernikova ◽  
◽  
Y. V. Ogorodnik ◽  
V. V. Prokopiv ◽  
◽  
...  
Keyword(s):  
Band Structure ◽  
Ab Initio ◽  
Ab Initio Calculation ◽  
Electronic Band Structure ◽  
Electronic Band

AB INITIO APPROACH TO STRUCTURAL, ELECTRONIC AND OPTICAL PROPERTIES OF B-, C- AND N-DOPED ANATASE

2010 ◽  
Vol 24 (31) ◽  
pp. 6049-6067 ◽  
Author(s):  
V. P. ZHUKOV ◽  
V. M. ZAINULLINA ◽  
E. V. CHULKOV
Keyword(s):  
Optical Properties ◽  
Optical Absorption ◽  
Band Structure ◽  
Crystal Lattice ◽  
Ab Initio ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Impurity Band ◽  
Theory Approach ◽  
Electronic Band

The effect of doping with boron, carbon and nitrogen on crystal lattice parameters, electronic band structure and optical absorption of anatase has been studied by means of an ab initio density functional theory approach. The investigations included optimization of crystal structure based on the pseudo-potential plane-wave approach. The spin-polarized calculations of the band structure with the account of on-site Coulomb correlations (LSDA+U) employing the tight-binding linear muffin-tin orbitals method (TB-LMTO) have also been performed. The evaluations of optical absorption were based on the calculations of dielectric function with local field effects taken into account. We find that the crystal lattice relaxation around the doping atoms produces noticeable changes in the band structure, magnetic state and optical properties of the doped compounds. The most considerable effects are the collapse of magnetic moment on carbon atom and an essential reduction of the optical absorption in the region of the impurity band — impurity band transitions. Comparing optical absorption for different kinds of doping and taking into account the intensity distribution of the solar light we come to the conclusion than the doping with boron is the most promising kind of doping for photocatalytic applications of the doped anatase.

Ab initio calculation on the Optical Properties of AA- Stacked two dimensional Graphene, Silicene, Germanene, and Stanene

2018 ◽  
Vol 1 (1) ◽  
pp. 46-50
Author(s):  
Rita John ◽  
Benita Merlin
Keyword(s):  
Optical Properties ◽  
Band Structure ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Complex Refractive Index ◽  
Single Layer ◽  
Generalized Gradient ◽  
Electronic Band ◽  
Wide Range ◽  
Optical Region

In this study, we have analyzed the electronic band structure and optical properties of AA-stacked bilayer graphene and its 2D analogues and compared the results with single layers. The calculations have been done using Density Functional Theory with Generalized Gradient Approximation as exchange correlation potential as in CASTEP. The study on electronic band structure shows the splitting of valence and conduction bands. A band gap of 0.342eV in graphene and an infinitesimally small gap in other 2D materials are generated. Similar to a single layer, AA-stacked bilayer materials also exhibit excellent optical properties throughout the optical region from infrared to ultraviolet. Optical properties are studied along both parallel (||) and perpendicular ( ) polarization directions. The complex dielectric function (ε) and the complex refractive index (N) are calculated. The calculated values of ε and N enable us to analyze optical absorption, reflectivity, conductivity, and the electron loss function. Inferences from the study of optical properties are presented. In general the optical properties are found to be enhanced compared to its corresponding single layer. The further study brings out greater inferences towards their direct application in the optical industry through a wide range of the optical spectrum.

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