Analyzing of Energy Band and Density of States of ZnO

2014 ◽  
Vol 492 ◽  
pp. 273-275
Author(s):  
Zhi Huan Lan ◽  
Man Yi Hou ◽  
Hong Yan Wang ◽  
Yi Guo Ji
Keyword(s):  
Electronic Structure ◽  
Plane Wave ◽  
Density Function ◽  
Density Of States ◽  
Energy Band ◽  
Function Theory ◽  
Energy Gap ◽  
Coulomb Repulsion ◽  
Density Function Theory ◽  
Full Potential

The electronic structure of ZnO is calculated by using an accurate full-potential linear plane-wave based on the density function theory and WIN2K package. The curves of energy band and density of states of ZnO are gained. The energy gap is 0.9eV that is better some of the computed results by theory approaches and smaller than the experimental value obtained by X spectra. After analyzing it is known that the coulomb repulsion between 3d state of Zn and 2p state of O is very strong leading to the increase in the energy of O2p and the energy gap become smaller.

Effect of Al, Ti and Cr Doping on Vanadium Dioxide (VO2) Analyzed by Density Function Theory (DFT) Method

2020 ◽  
Vol 20 (3) ◽  
pp. 1651-1659 ◽  
Author(s):  
Hongmei Zhu ◽  
Zhengjie Zhang ◽  
Xuchuan Jiang
Keyword(s):  
Electronic Structure ◽  
Band Gap ◽  
Density Function ◽  
Vanadium Dioxide ◽  
Function Theory ◽  
Dft Method ◽  
Density Function Theory ◽  
Atomic Scale ◽  
Elemental Doping ◽  
Cr Doping

Density function theory (DFT) method was developed and applied for fundamentally understanding the doping effect of various metals (Al, Ti and Cr) on vanadium dioxide (VO2). The substitution doping of Al, Ti and Cr in VO2 could lead to significant changes in electronic structure, band gap and optical property. Different from physical experiments, the DFT method could be utilized for fundamental understandings at an atomic scale. It was found via DFT calculations that: (i) Al doping caused a slightly distorted octahedron in monoclinic VO2(M), and narrowed the band gap of VO2(M) due to the upward shift of the valence band (VB), while Cr doping narrowed the band gap because of the downward shift of the conduction band (CB); (ii) Ti doping slightly widened the band gap of VO2(M); and (iii) the optical reflectivity of VO2(M) decreased after substitution doping low-valent metals (e.g., Al). This study will be beneficial for designing and controlling elemental doping to obtain metal oxide nanocomposites with unique band gap and electronic structure for thermochromic energy saving applications.

scholarly journals Design Pollution Gas Sensor Using Graphene Ribbon: Density Function Theory (DFT)

2021 ◽  
Author(s):  
Ruaa.S. Al-Hasnawy ◽  
Ali S. Shaker ◽  
Muntather H Albosaabar ◽  
Zahraa A. Al-Maamouri ◽  
Hamed A. Al-taee
Keyword(s):  
Density Function ◽  
Adsorption Energy ◽  
Function Theory ◽  
Energy Gap ◽  
Physical Adsorption ◽  
Wave Length ◽  
Density Function Theory ◽  
Chemical Adsorption ◽  
Graphene Ribbon ◽  
Gas Molecule

Abstract Density Function theory (DFT) calculation used to employed ground and excitation states for graphene ribbons, types of adsorption, energy gap, maximum wave length and optical band gap. Adsorption energy showed that CO2 gas molecule have chemical adsorption in distance 1 and 1.5 Angstrom, distance 2 and 2.5 Angstrom appear physical adsorption, adsorption energy decreased when distance between surface and gas molecule increasing. Resulting from chemical adsorption energy gap change with distance 1 and 1.5 Angstrom because attract gas molecule with surface. Excitation energy for nano system in sample 1 and 4 shifted to low wavelength (blue shift) change from 1018 nm to 993 nm and 718 nm on series. Other sample have red shift and energy gap becoming open. Result showed that graphene ribbon sense carbon dioxide gas (CO2).

The Mechanism of In and Ge Occurrence in Sphalerite Crystal and the Influence on Properties: A DFT (Density Function Theory) Simulation

2017 ◽  
Vol 262 ◽  
pp. 303-306
Author(s):  
Lin Lin Tong ◽  
Hong Ying Yang ◽  
Jia Ning Xu ◽  
Peng Cheng Xu ◽  
Chao Li
Keyword(s):  
Density Function ◽  
Density Of States ◽  
Function Theory ◽  
Density Function Theory

In and Ge can be found in Sphalerite crystal which can influence bio-leaching properties of Sphalerite significantly. Occurrence states of In and Ge in Sphalerite crystal and their influence on Sphalerite was calculated by Castep package. The most stable occurrence states are In and Ge substitute for Zn atom in Sphalerite crystal. When In and Ge existed in Sphalerite crystal, the Density of states (DOS) of Sphalerite crystal moved to left, meaning a more reducibility structure. It can explain why In and Ge bearing Sphalerite is easier to bio-leach than the pure sphalerite.

Density Function Theory Calculation of Crystal Properties and Electronic Structure of δ-Pu

2017 ◽  
Vol 727 ◽  
pp. 712-717
Author(s):  
Yuan Jiang Zhu ◽  
Yun Liang Gao
Keyword(s):  
Electronic Structure ◽  
Density Function ◽  
Elastic Properties ◽  
Density Functional ◽  
Function Theory ◽  
Local Density ◽  
Density Function Theory ◽  
Partial Density ◽  
Density Of State ◽  
Lattice Constants

In this paper, lattice constants, elastic properties and electronic structure of δ-Pu are investigated by means of plane wave pseudo-potential method (PWP) based on density function theory (DFT). A variety of density functional theory methods have been adopted to calculate the crystal structure and elastic property of δ-Pu, and it is found that the lattice constants, bulk modulus B, shear modulus G, Young's modulus E and Poisson's ratio ν calculated by spin polarization local density approximation (SP+LDA) method are in best agreement with experimental values. The electronic structure have been investigated within the framework of LDA+U, and the band structure, density of state (DOS) and partial density of state (PDOS) are calculated. Calculation results of elastic properties and electronic structure show that, δ-Pu shows obvious metallicity and well ductility, its electrons are strongly corrected and the DOS in the vicinity of the Fermi Level is mainly contributed by 5f electrons.

Theory Study on the Geometric Structures and Electronic Properties of PtnN0,±(n=1-5) Clusters

2012 ◽  
Vol 516-517 ◽  
pp. 1889-1892 ◽  
Author(s):  
Xiu Rong Zhang ◽  
Lin Yin ◽  
Wei Jun Li ◽  
Hui Shuai Tang
Keyword(s):  
Electronic Structure ◽  
Electronic Properties ◽  
Density Function ◽  
Ground State ◽  
Function Theory ◽  
Density Function Theory ◽  
Geometric Structures ◽  
Ground State Structures

The geometric structures of PtNN0,± clusters are optimized by the B3LYP/LANL2DZ method of density function theory, the ground state structures are obtained, and the electronic structure are studied. The results show: the N atoms gain the charge when the clusters are formed, but some Pt atoms gain the charge and other Pt atoms lose the charge. N atom and Pt atom have internal heterozygous, and the spd hybridized between Pt atoms and N atoms are increasing with cluster s’ sizes.

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