scholarly journals First principles DFT calculations of the optical properties of A4BX6 group crystals

2021 ◽  
Vol 22 (1) ◽  
pp. 117-122
Author(s):  
H. Ilchuk ◽  
M. Solovyov ◽  
I. Lopatynskyi ◽  
F. Honchar ◽  
F. Tsyupko
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Energy Band ◽  
Density Functional ◽  
Near Infrared ◽  
Infrared Region ◽  
Energy Structure ◽  
Generalized Gradient ◽  
Reflection Index ◽  
Functional Theory

The results of investigating of the electron band energy structure and optical properties of A4BX6 (Tl4HgI6 and Tl4CdI6) group crystals are presented. The energy band structures of Tl4HgI6 and Tl4CdI6 crystals are calculated from the first principles within generalized gradient approximation (GGA). The band structure and reflection index were calculated using a pseudopotential method in the framework of density functional theory. Optical absorption edge in Tl4HgI6 and Tl4CdI6 is formed by direct optical transitions. The spectral dependence of the reflection index was calculated on the basis of the energy band results with using the Kramers–Kronig method. The spectra show pronounced anisotropy in E||a(b) and E||c polarizations. It was found the anomalous by large values of the birefringence (Δn > 0.18 for Tl4HgI6 and Δn > 0.03 for Tl4CdI6) in the visible and near infrared region.

Optical properties of Yb-doped LaB6 from first-principles calculation

2016 ◽  
Vol 30 (07) ◽  
pp. 1650091 ◽  
Author(s):  
Luomeng Chao ◽  
Lihong Bao ◽  
Wei Wei ◽  
O. Tegus
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Density Functional ◽  
Near Infrared ◽  
Infrared Region ◽  
Transmission Peak ◽  
First Principles Calculation ◽  
First Principles Calculations ◽  
Plasmon Energy ◽  
Functional Theory

The optical properties of Yb-doped LaB6 have been investigated by first-principles calculations within the framework of density functional theory. The results show that the Yb [Formula: see text] states at near Fermi surface affect their optical properties and the Yb-doping leads to a reduction of the plasmon energy of LaB6, i.e. a redshift of the position of transmission peak in the visible-near infrared region. This study offers a theoretical prediction for the design and application of Yb-doped LaB6 as an optoelectronic material.

scholarly journals First Principles Study on the Electronic Structure and Optical Properties of La Doped YB6 Crystals

2021 ◽  
pp. X
Author(s):  
Hongbo TANG ◽  
Qiuyue LI ◽  
Jian ZHOU ◽  
Lihua XIAO ◽  
Ping PENG
Keyword(s):  
Density Functional Theory ◽  
Optical Properties ◽  
Electronic Structure ◽  
First Principles ◽  
Density Functional ◽  
Near Infrared ◽  
Infrared Light ◽  
First Principles Calculations ◽  
Functional Theory ◽  
La Doped

Received 03 January 2020; accepted 17 June 2020 We have investigated the optical properties of La (0, 0.125, 0.250) doped YB6 by means of first-principles calculations within the framework of density functional theory. It was found that electronic and optical properties of YB6 crystals varied remarkably when Y atoms were replaced with La atoms. Furthermore, with increasing content of La in YB6 crystals from 12.5 % to 25 % reflectivity and absorption coefficient of near infrared light decreased obviously, while the transmittance was enhanced.

scholarly journals Structural, electronic, and optical properties of quaternary alloys Al0.50Ga0.50NxSb1-x : a first-principles study

2020 ◽  
Vol 66 (6 Nov-Dec) ◽  
pp. 790
Author(s):  
M. Berber ◽  
N. Bouzouira ◽  
M. Mebrek ◽  
A. Boudali ◽  
H. Abid ◽  
...  
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Infrared Region ◽  
Generalized Gradient ◽  
Quaternary Alloys ◽  
Metallic Behavior ◽  
Functional Theory ◽  
Electronic And Optical Properties ◽  
Correlation Potential ◽  
First Time

In this study, we have employed the first-principle methods based on density functional theory to investigate the structural, electronic and optical properties of Al0.50Ga0.50NxSb1-x in zincblende structure. The exchange and correlation potential is described by the generalized gradient approximation of Perdew, Burke and Ernzerhof (GGA-PBEsol) coupled with TB-mBJ approaches. The studied structures shows that all structures are semiconductors and have a direct bandgap except Al0.50Ga0.50N0.25Sb0.75 which has a semi-metallic behavior. The optical properties such as refractive index, extinction coefficient and optical conductivity are discussed in detail. Our result shows these materials are considered as promising materials for optoelectronic applications in the visible and infrared region. To our knowledge this is the first time that a study has been done on this alloy and we would like it to serve as a reference for the next studies.

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.

First-Principles Study of Electronic and Optical Properties in Wurtzite ZnCoO Alloys

2013 ◽  
Vol 333-335 ◽  
pp. 1847-1852
Author(s):  
Ming Zhu Li ◽  
Li Mei Song ◽  
Shan Wang
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Density Functional ◽  
Optical Constants ◽  
Density Functional Theory Calculations ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Electronic And Optical Properties ◽  
The Density Functional Theory ◽  
Co Concentration

We perform a first-principles simulation to research the electronic and optical properties of wurtzite Zn1-xCoxO. The simulations are based on the Perdew-Burke-Ernzerhof form of generalized gradient approximation within the density functional theory. Calculations are carried out in different concentrations. With increasing Co concentration, the band gap of Zn1-xCoxO decreases due to the shift of valence band. Besides, it is shown that the insertion of Co atom leads to redshift of the optical absorption edge. Meanwhile, the optical constants of pure ZnO and ZnCoO alloys such as loss function, refractive index and reflectivity, are discussed.

scholarly journals First Principles Study of Electronic and Optical Properties of Pristine and X (Cu, Ag And Au) Doped BiOBr

2018 ◽  
Vol 22 (2) ◽  
pp. 63-69 ◽  
Author(s):  
Samir Paudel ◽  
Puspa Raj Adhikari ◽  
Om Prakash Upadhyay ◽  
Gopi Chandra Kaphle ◽  
Anurag Srivastava
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
First Principles ◽  
Electronic Structures ◽  
Density Functional ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Ab Initio Approach ◽  
Indirect Band Gap ◽  
Standard Density

The electronic structures and optical properties of pristine BiOBr and Cu, Ag and Au doped BiOBr have been analyzed by using a standard density functional theory based ab-initio approach employing generalized gradient approximation through revised Perdew Burke Ernzerhoff type parameterization. The calculation shows that both the doped and pristine BiOBr have indirect band gap, the band gap of the pristine BiOBr found 2.22eV, whereas band gap significantly reduced after doping Cu, Ag and Au on BiOBr. The band gap of Cu, Ag and Au doped BiOBr are 1.2eV, 0.9eV and 1.76eV respectively. The optical properties have been studied through dielectric function, both pure and doped BiOBr shows anisotropic nature. Journal of Institute of Science and TechnologyVolume 22, Issue 2, January 2018, page: 63-69 

Electronic structure of cubic BaTbO3 from first-principles pseudopotential calculations

2006 ◽  
Vol 84 (2) ◽  
pp. 115-120 ◽  
Author(s):  
G Y Gao ◽  
K L Yao ◽  
Z L Liu
Keyword(s):  
Electronic Structure ◽  
First Principles ◽  
Density Functional ◽  
First Principles Calculations ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Exchange Correlation ◽  
Pseudopotential Calculations ◽  
Correlation Potential ◽  
Density Contour

First-principles calculations of the electronic structure are performed for cubic BaTbO3 using the plane-wave pseudopotential method within the framework of density functional theory and using the generalized gradient approximation for the exchange-correlation potential. Our calculations show that cubic BaTbO3 is metallic, and that this metallic character is mainly governed by the Tb 4f electrons and the hybridization between the Tb 5d and O 2p states. From the analysis of the density of states, band structure, and charge density contour, we find that the chemical bonding between Tb and O is covalent while that between Ba and TbO3 is ionic. PACS Nos.: 71.15.Mb, 71.20.-b

scholarly journals Oxygen vacancy and doping atom effect on electronic structure and optical properties of Cd2SnO4

RSC Advances ◽  
2018 ◽  
Vol 8 (2) ◽  
pp. 640-646 ◽  
Author(s):  
Mei Tang ◽  
JiaXiang Shang ◽  
Yue Zhang
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
Oxygen Vacancy ◽  
Density Functional ◽  
Generalized Gradient ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
La Doped ◽  
Doping Atom ◽  
Atom Effect

The electronic structure and optical properties of oxygen vacancy and La-doped Cd2SnO4 were calculated using the plane-wave-based pseudopotential method based on the density functional theory (DFT) within the generalized gradient approximation (GGA).

First-Principles Study of Interaction of Lithium Atoms with (3, 3) Carbon Nanotubes

2014 ◽  
Vol 687-691 ◽  
pp. 4311-4314 ◽  
Author(s):  
Shun Fu Xu ◽  
Ling Min Li
Keyword(s):  
Carbon Nanotubes ◽  
First Principles ◽  
Density Functional ◽  
Vacancy Defect ◽  
Single Wall Carbon Nanotubes ◽  
Generalized Gradient ◽  
Hydrogen Atoms ◽  
Functional Theory ◽  
Vacancy Defects ◽  
Adsorption Mechanisms

In this paper, we have employed first-principles calculations to investigate the adsorption mechanisms of one lithium atom on the sidewalls of 1/2/3 H-adsorbed indefective/defective (3, 3) single-wall carbon nanotubes (CNTs) which have vacancy defects. Our calculations are performed within density functional theory (DFT) under the generalized gradient approximation (GGA) of Perdew, Burke, and Ernzerhof (PBE).Our results show that the lithium atoms strongly binds to the H-adsorbed (3, 3) nanotube. Lithium atoms can chemically adsorb on (3, 3) nanotube with the vacancy defect (MVD) without any energy barrier. The lithium adsorption will enhance the electrical conductivity of the nanotube. Further more, the structure of the (3, 3) nanotube with the MVD and hydrogen atoms will become more stable after the three kinds of lithium adsorption.

scholarly journals Many-Body Effects in FeN4 Center Embedded in Graphene

2020 ◽  
Vol 10 (7) ◽  
pp. 2542 ◽  
Author(s):  
Andrew Allerdt ◽  
Hasnain Hafiz ◽  
Bernardo Barbiellini ◽  
Arun Bansil ◽  
Adrian E. Feiguin
Keyword(s):  
Transition Metal Complexes ◽  
First Principles ◽  
Density Functional ◽  
Coulomb Repulsion ◽  
Density Matrix Renormalization Group ◽  
Orbital Interaction ◽  
Many Body ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Density Matrix Renormalization

We introduce a computational approach to study porphyrin-like transition metal complexes, bridging density functional theory and exact many-body techniques, such as the density matrix renormalization group (DMRG). We first derive a multi-orbital Anderson impurity Hamiltonian starting from first principles considerations that qualitatively reproduce generalized gradient approximation (GGA)+U results when ignoring inter-orbital Coulomb repulsion U ′ and Hund exchange J. An exact canonical transformation is used to reduce the dimensionality of the problem and make it amenable to DMRG calculations, including all many-body terms (both intra- and inter-orbital), which are treated in a numerically exact way. We apply this technique to FeN 4 centers in graphene and show that the inclusion of these terms has dramatic effects: as the iron orbitals become single occupied due to the Coulomb repulsion, the inter-orbital interaction further reduces the occupation, yielding a non-monotonic behavior of the magnetic moment as a function of the interactions, with maximum polarization only in a small window at intermediate values of the parameters. Furthermore, U ′ changes the relative position of the peaks in the density of states, particularly on the iron d z 2 orbital, which is expected to affect the binding of ligands greatly.

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