Quantifying Temperature Dependence of Electronic Band Gaps and Optical Properties in SnO2 and SnO via First-Principles Simulations

2021 ◽  
Author(s):  
Jongwoo Park ◽  
Wissam A. Saidi ◽  
Benjamin Chorpening ◽  
Yuhua Duan
Keyword(s):  
Optical Properties ◽  
Temperature Dependence ◽  
First Principles ◽  
Band Gaps ◽  
Electronic Band

First-principles investigation of the electronic band structures and optical properties of quaternary ABaMQ4 (A = Rb, Cs; M = P, V; and Q = S) metal chalcogenides

2018 ◽  
Vol 32 (30) ◽  
pp. 1850337
Author(s):  
Shahid Ullah ◽  
Hayat Ullah ◽  
Abdullah Yar ◽  
Sikander Azam ◽  
A. Laref
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Density Functional ◽  
Correlation Energy ◽  
Electronic Charge ◽  
Electromagnetic Spectrum ◽  
Metal Chalcogenides ◽  
Electronic Band ◽  
Charge Densities ◽  
Electronic Band Structures

In this paper, we study the optoelectronic properties of quaternary metal chalcogenide semiconductor ABaMQ4 (A = Rb, Cs; M = P, V; and Q = S) compounds using state-of-the-art density functional theory (DFT) with TB-mBJ approximation for the treatment of exchange-correlation energy. In particular, the electronic and optical properties of the relaxed geometries of these compounds are investigated. Our first-principles ab-initio calculations show that the CsBaPS4 and RbBaPS4 compounds have direct bandgaps whereas the CsBaVS4 compound exhibits indirect bandgap nature. Importantly, the theoretically calculated values of the bandgaps of the compounds are consistent with experiment. Furthermore, our analysis of the electronic charge densities of these compounds indicates that the above quaternary chalcogenides have mixed covalent and ionic bonding characters. The effective masses of these compounds are also calculated which provide very useful information about the band structure and transport characteristics of the investigated compounds. Similarly, high absorptivity in the visible and ultraviolet regions of the electromagnetic spectrum possibly predicts and indicates the importance of these materials for potential optoelectronic applications in this range.

scholarly journals Accurate Prediction of Band Structure of FeS2: A Hard Quest of Advanced First-Principles Approaches

2021 ◽  
Vol 9 ◽  
Author(s):  
Min-Ye Zhang ◽  
Hong Jiang
Keyword(s):  
Band Structure ◽  
First Principles ◽  
High Energy ◽  
Accurate Prediction ◽  
Band Gaps ◽  
Full Potential ◽  
Band Structures ◽  
Electronic Band ◽  
Fundamental Band ◽  
Hybrid Functionals

The pyrite and marcasite polymorphs of FeS2 have attracted considerable interests for their potential applications in optoelectronic devices because of their appropriate electronic and optical properties. Controversies regarding their fundamental band gaps remain in both experimental and theoretical materials research of FeS2. In this work, we present a systematic theoretical investigation into the electronic band structures of the two polymorphs by using many-body perturbation theory with the GW approximation implemented in the full-potential linearized augmented plane waves (FP-LAPW) framework. By comparing the quasi-particle (QP) band structures computed with the conventional LAPW basis and the one extended by high-energy local orbitals (HLOs), denoted as LAPW + HLOs, we find that one-shot or partially self-consistent GW (G0W0 and GW0, respectively) on top of the Perdew-Burke-Ernzerhof (PBE) generalized gradient approximation with a converged LAPW + HLOs basis is able to remedy the artifact reported in the previous GW calculations, and leads to overall good agreement with experiment for the fundamental band gaps of the two polymorphs. Density of states calculated from G0W0@PBE with the converged LAPW + HLOs basis agrees well with the energy distribution curves from photo-electron spectroscopy for pyrite. We have also investigated the performances of several hybrid functionals, which were previously shown to be able to predict band gaps of many insulating systems with accuracy close or comparable to GW. It is shown that the hybrid functionals considered in general fail badly to describe the band structures of FeS2 polymorphs. This work indicates that accurate prediction of electronic band structure of FeS2 poses a stringent test on state-of-the-art first-principles approaches, and the G0W0 method based on semi-local approximation performs well for this difficult system if it is practiced with well-converged numerical accuracy.

scholarly journals First principles study of structure, electronic and optical properties of Y3Fe5O12 in cubic and trigonal phases

2015 ◽  
Vol 33 (1) ◽  
pp. 169-174 ◽  
Author(s):  
Shen Tao ◽  
Hu Chao ◽  
Dai Hailong ◽  
Yang Wenlong ◽  
Liu Hongchen ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Energy Loss ◽  
First Principles ◽  
Structural Parameters ◽  
Band Gaps ◽  
First Principles Calculations ◽  
Electronic And Optical Properties ◽  
Direct Band ◽  
Experimental Values

AbstractFirst principles calculations have been performed to investigate the structure, electronic and optical properties of Y3Fe5O12. Both the cubic and trigonal phases have been considered in our calculation. The calculated structural parameters are slightly larger than the experimental values. The band structures show that Y3Fe5O12 in cubic and trigonal phases have direct band gaps of 0.65 and 0.17 eV. The calculations of dielectric function, absorption, extinction coefficient, refractive index, energy loss function and reflectivity are presented.

The effect of substitutional doping of Yb2+ on structural, electronic, and optical properties of CsCaX3 (X: Cl, Br, I) phosphors: A first-principles study

2021 ◽  
Author(s):  
Rashid Khan ◽  
Kaleem Ur Rahman ◽  
Qingmin Zhang ◽  
Altaf Ur Rahman ◽  
Sikander Azam ◽  
...  
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Dielectric Susceptibility ◽  
Hybrid Functional ◽  
Generalized Gradient ◽  
Electronic Band ◽  
Electronic And Optical Properties ◽  
Substitutional Doping ◽  
Bandgap Semiconductors ◽  
Magnetic Insulator

Abstract Using first-principles calculations, the effects of Yb$^{2+}$ substitutional doping on structural, electronic, and optical properties of a series of perovskite compounds CsCaX$_3$ (X: Cl, Br, I), have been investigated. We employed generalized gradient approximation (GGA) and HSE hybrid functional to study the electronic and optical properties. A series of pristine CsCaX$_3$(X: Cl, Br, I) is characterized as a non-magnetic insulator with indirect bandgap perovskite materials. These phosphor materials are suitable candidates for doping with lanthanide series elements to tune their electronic bandgaps according to our requirements because of their wide bandgaps. The calculated electronic bandgaps of CsCaX$_3$ (X: Cl, Br, I) are 3.7 eV(GGA) and 4.5 eV (HSE) for CsCaI$_3$, 4.5 eV (GGA) and 5.3 eV (HSE) for CsCaBr$_3$, and 5.4 eV (GGA) and 6.4 eV (HSE) for CsCaCl$_3$. According to formation energies, the Yb$^{2+}$ doped at the Ca-site is thermodynamically more stable as compared to all possible atomic sites. The electronic band structures show that the Yb$^{2+}$ doping induces defective states within the bandgaps of pristine CsCaX$_3$. As a result, the Yb$^{2+}$ doped CsCaX$_3$ (X: Cl, Br, I) become the direct bandgap semiconductors. The defective states above the VBM are produced due to the $f$-orbital of the Yb atom. The impurity states near the CBM are induced due to the major contribution of $d$-orbital of the Yb atom and the minor contribution of $s$-orbital of the Cs atom. The real and imaginary parts of the dielectric function, optical reflectivity, electron energy loss spectrum, extinction coefficient, and refractive index of pristine and Yb$^{2+}$ doped CsCaX$_3$ were studied. The optical dispersion results of dielectric susceptibility closely match their relevant electronic structure and align with previously reported theoretical and experimental data. We conclude that the Yb$^{2+}$ doped CsCaX$_3$ (X: Cl, Br, I) are appealing candidates for optoelectronic devices.

scholarly journals First–Principles Investigation of the Structural, Elastic, Electronic, and Optical Properties of α– and β–SrZrS3: Implications for Photovoltaic Applications

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 978
Author(s):  
Henry Igwebuike Eya ◽  
Esidor Ntsoenzok ◽  
Nelson Y. Dzade
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Density Functional ◽  
Visible Region ◽  
Charge Carriers ◽  
Band Gaps ◽  
Strong Light ◽  
Electronic And Optical Properties ◽  
Optical Absorbance ◽  
Effective Masses

Transition metal perovskite chalcogenides are attractive solar absorber materials for renewable energy applications. Herein, we present the first–principles screened hybrid density functional theory analyses of the structural, elastic, electronic and optical properties of the two structure modifications of strontium zirconium sulfide (needle–like α–SrZrS3 and distorted β–SrZrS3 phases). Through the analysis of the predicted electronic structures, we show that both α– and β–SrZrS3 materials are direct band gaps absorbers, with calculated band gaps of 1.38, and 1.95 eV, respectively, in close agreement with estimates from diffuse–reflectance measurements. A strong light absorption in the visible region is predicted for the α– and β–SrZrS3, as reflected in their high optical absorbance (in the order of 105 cm−1), with the β–SrZrS3 phase showing stronger absorption than the α–SrZrS3 phase. We also report the first theoretical prediction of effective masses of photo-generated charge carriers in α– and β–SrZrS3 materials. Predicted small effective masses of holes and electrons at the valence, and conduction bands, respectively, point to high mobility (high conductivity) and low recombination rate of photo-generated charge carriers in α– and β–SrZrS3 materials, which are necessary for efficient photovoltaic conversion.

First Principles Calculations of Electronic Band Structure and Optical Properties of Cr-Doped ZnO

2009 ◽  
Vol 113 (19) ◽  
pp. 8460-8464 ◽  
Author(s):  
Luyan Li ◽  
Weihua Wang ◽  
Hui Liu ◽  
Xindian Liu ◽  
Qinggong Song ◽  
...  
Keyword(s):  
Optical Properties ◽  
Band Structure ◽  
First Principles ◽  
Electronic Band Structure ◽  
First Principles Calculations ◽  
Electronic Band ◽  
Doped Zno

scholarly journals First Principles Study on the Structural, Elastic, Electronic and Optical Properties of Cubic ‘Half-Heusler’ Alloy RuVAs Under Pressure

2020 ◽  
pp. 51-63 ◽  
Keyword(s):  
Optical Properties ◽  
Band Structure ◽  
Bulk Modulus ◽  
Band Gap ◽  
Elastic Constants ◽  
First Principles ◽  
Theoretical Data ◽  
Lattice Parameter ◽  
Electronic Band ◽  
Electronic And Optical Properties

The pressure effect (0 to 40 GPa) on the structural, elastic, electronic, and optical properties of half-metallic compound RuVAs has been investigated employing the DFT based on the first-principles method. The CASTEP computer code is used for this investigation. The calculated lattice parameter show slide deviation from the synthesized and other theoretical data. The normalized lattice parameter and volume are decreased with increasing pressure. The zero pressure elastic constants and also the pressure-dependent elastic constants are positive up to 40 GPa and satisfy the Born stability condition which ensured that the compound RuVAs is stable in nature. At zero pressure, the electronic band gap of 0.159 eV is observed from the band structure calculations which ensured the semimetallic nature of RuVAs. No band gap is observed in the electronic band structure at 40 GPa which indicates the occurrence of phase transition of compound RuVAs at this pressure. We have calculated the value of bulk modulus B, shear modulus G, Young’s modulus E, Pugh ratio B/G, Poisson’s ratio ν and anisotropy factor A of this compound by using the Voigt-Reuss-Hill (VRH) averaging scheme under pressure. The bulk modulus shows a linear response to pressure so that the hardness of this material is increased with increasing pressure. Furthermore, the optical properties such as reflectivity, absorptivity, conductivity, dielectric constant, refractive index, and loss function of RuVAs were evaluated and discussed under pressure up to 40 GPa.

scholarly journals Novel ultra-hard hexacarbon allotropes from first principles

2022 ◽  
Author(s):  
Samir F. Matar ◽  
Vladimir L. Solozhenko
Keyword(s):  
Elastic Constants ◽  
Vickers Hardness ◽  
Ground State ◽  
First Principles ◽  
Geometry Optimization ◽  
Band Gaps ◽  
Electronic Band ◽  
Carbon Allotropes ◽  
Ground State Structures ◽  
Electronic Band Structures

Novel ultra-hard hexacarbon C6 allotropes are proposed based on crystal chemistry rationale and geometry optimization onto ground state structures. Similar to diamond, the orthorhombic, tetragonal and trigonal C6 are cohesive networks of C4 tetrahedra illustrated by charge density projections exhibiting sp3-like carbon hybridization. All three allotropes are identified as mechanically (elastic constants) and dynamically (phonons) stable. The electronic band structures are characteristic of insulators with large band gaps of 4 to 5 eV, like diamond. From three different models evaluating Vickers hardness HV, all new carbon allotropes are identified as ultra-hard.

Electronic and optical properties of pentagonal-B2C monolayer: A first-principles calculation

2017 ◽  
Vol 31 (08) ◽  
pp. 1750044 ◽  
Author(s):  
Mosayeb Naseri ◽  
Jafar Jalilian ◽  
A. H. Reshak
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Valence Band Maximum ◽  
First Principles Calculation ◽  
Electronic Band ◽  
Electronic And Optical Properties ◽  
Energy Consideration ◽  
Normal Light

The electronic and optical properties of pentagonal B2C (penta-B2C) monolayer are investigated by means of the first-principles calculations in the framework of the density functional theory. The cohesive energy consideration confirms the good stability of the B2C nanostructure in this phase. The electronic band structure reveals that the valence band maximum (VBM) is located at [Formula: see text]-point of the first Brillouin zone (BZ) whereas the conduction band minimum (CBM) is situated at the center of the BZ, resulting in an indirect energy bandgap of about 1.5 eV. Furthermore, a calculated low absorption and low reflection of the material in low energy ranges denote the transparency of the B2C monolayer in the investigated range for normal light incidence. The obtained results may find application in fabrication of future opto-electronic devices.

scholarly journals First Principles Study of Copper Sulfides (for Applications as Photoconductors)

2012 ◽  
Vol 730-732 ◽  
pp. 111-116 ◽  
Author(s):  
Jorge A. Ferreira ◽  
M. Helena Braga
Keyword(s):  
First Principles ◽  
Electronic Band Structure ◽  
Band Gaps ◽  
Solid Solution Series ◽  
Electronic Band ◽  
Copper Sulfides ◽  
Direct Band Gap ◽  
Photovoltaic Materials ◽  
Complete Solid Solution ◽  
Direct Band

The Tetrahedrite’s family constitutes a complete solid-solution series, and is among the most frequent complex sulfides in Nature. This kind of structure can be generically expressed by the composition, Cu12Sb4S13. We have calculated the electronic band structure of Cu12Sb4S13 and Ag6Cu6Sb4S13 (with band gaps of 1.24 and 1.20 eV, respectively) to demonstrate that different elements occupying certain sites of the crystal structure will make a difference in what concerns the conduction process in Tetrahedrites. We will use this effect and ab initio calculations to show that the electronic properties of these compounds make them promising candidates as solar cells photovoltaic materials since not only they possess a direct band gap but their energy falls within the range of energies of photovoltaics. Moreover, we can optimize these properties by doping and substituting ions furthermore. Mechanical properties were also calculated for both compounds and will be compared.

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