Electronic Structure of Wurtzite Ga0.75Al0.25N: A First Principle Calculation

2014 ◽  
Vol 556-562 ◽  
pp. 43-46
Author(s):  
Ming Zhu Yang ◽  
Mei Shan Wang
Keyword(s):  
Density Functional ◽  
First Principle ◽  
Functional Theory ◽  
Principle Calculation ◽  
First Principle Calculation ◽  
Solar Blind ◽  
Direct Band ◽  
Total Energies ◽  
Pseudo Potential ◽  
Theoretical Foundations

In order to lay theoretical foundations for preparation of Ga0.75Al0.25N photocathodes, research on ternary Ш-V alloys Ga0.75Al0.25N are carried on. Using CASTEP software package based on density functional theory within a plane wave ultrasoft pseudo potential scheme, total energies, band structures, density of states, and charge distribution of three different structures of wurtzite Ga0.75Al0.25N are calculated. Results show that the structure in which Al atoms in para-positon of interlayer is most stable. Ga0.75Al0.25N is semiconductor with direct band gap. The threshold wavelength is 321.8nm which can satisfy the need of preparation of “solar blind” photocathodes.

scholarly journals First Principle Study on Atomic Scale Structures of Cathode in Aluminium-ion Battery Using Various van der Waals Corrections

2020 ◽  
Vol 213 ◽  
pp. 01023
Author(s):  
Kaihao Geng ◽  
Haining Cao ◽  
Meng-Chang Lin
Keyword(s):  
Density Functional ◽  
Van Der Waals ◽  
Structural Features ◽  
Atomic Scale ◽  
First Principle ◽  
Functional Theory ◽  
Principle Calculation ◽  
First Principle Calculation ◽  
Aluminium Ion ◽  
Scale Structures

There is still controversy on the atomistic configuration of aluminium-ion batteries (AIB) cathode when using first principle calculation based on density functional theory (DFT). We examined the relevant cathodic structures of Al/graphite battery by employing several van der Waals (vdW) corrections. Among them, DFT-TS method was determined to be a better dispersion correction in correctly rendering structural features already found through experiment investigations. The systematic comparison paved the way to the choice of vdW parameters in first principle calculation of graphitic electrode.

Enhanced ferromagnetic properties of Cu doped two-dimensional GaN monolayer

2015 ◽  
Vol 26 (01) ◽  
pp. 1550009 ◽  
Author(s):  
Fayyaz Hussain ◽  
Y. Q. Cai ◽  
M. Junaid Iqbal Khan ◽  
Muhammad Imran ◽  
Muhammad Rashid ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Magnetic Properties ◽  
Density Functional ◽  
Magnetic Coupling ◽  
First Principle ◽  
Two Dimensional ◽  
Functional Theory ◽  
Principle Calculation ◽  
First Principle Calculation ◽  
Cu Dopant

We demonstrate enhanced ferromagnetism in copper doped two-dimensional GaN monolayer ( GaN -ML). Our first principle calculation based on density functional theory predicted that nonmagnetic Cu -dopant with concentration of 6.25% to be ferromagnetic (FM) in 2D GaN layer which carries a magnetic moment of 2.0 μB per Cu atom and it is found to be long range magnetic coupling among the Cu -dopant. The Cu-dopant in 2D GaN -ML which can be explained in terms of p-d hybridization at Curie temperature and this dopant prefer the FM behavior in 2D GaN layer. Hence Cu doped 2D GaN layer shows strong magnetic properties so that it is a promising material in the field of spintronics.

Half-metallic ferromagnetism in hypothetical wurtzite structure chromium chalcogenides

2004 ◽  
Vol 19 (9) ◽  
pp. 2738-2741 ◽  
Author(s):  
Ming Zhang ◽  
Ekkes Brück ◽  
Frank R. de Boer ◽  
Guodong Liu ◽  
Haining Hu ◽  
...  
Keyword(s):  
Density Functional ◽  
Wurtzite Structure ◽  
First Principle ◽  
Half Metallicity ◽  
Functional Theory ◽  
Half Metallic ◽  
Principle Calculation ◽  
First Principle Calculation ◽  
Metallic Ferromagnetism ◽  
Half Metallic Ferromagnetism

The hypothetical wurtzite structure chromium chalcogenides were investigated through first-principle calculation within density-functional theory. All compounds are predicted to be true half-metallic ferromagnets with an integer Bohr magneton of 4 μB per unit. Their half-metallic gaps are 1.147, 0.885, and 0.247 eV at their equilibrium volumes for wurtzite-type CrM (M = S, Se, and Te), respectively. The half-metallicity can be maintained even when volumes are expanded by more than 20% for all compounds and compressed by more than 20%, 20%, and 5%, for CrS, CrSe, and CrTe, respectively.

scholarly journals Surface Properties and Floatability Comparison of Aegirite and Specularite by Density Functional Theory Study and Experiment

Minerals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 782 ◽  
Author(s):  
Mingyang Li ◽  
Jun Liu ◽  
Xiangpeng Gao ◽  
Yiming Hu ◽  
Xiong Tong ◽  
...  
Keyword(s):  
Surface Properties ◽  
Density Functional ◽  
Surface Relaxation ◽  
First Principle ◽  
Density Functional Theory Study ◽  
Functional Theory ◽  
Potential Measurement ◽  
Principle Calculation ◽  
First Principle Calculation ◽  
Bond Population

Understanding the differences in surface properties between aegirite and specularite is of great significance to study their separation. In this work, the surface properties of aegirite and specularite, as well as their relationships to floatability, have been explored by first principle calculation, flotation, and Zeta potential measurement. The surface relaxation indicated that the specularite (001) surface appeared to show more surface reconstruction. The unsatisfied bond properties, Mulliken bond population, and surface charge showed that the floatability of specularite was superior to that of aegirite. The flotation results showed that the hydrophobicity of specularite was higher than that of aegirite with dodecylamine (DDA) as the collector. It is infeasible to separate specularite from aegirite by flotation using starch as the depressant, and research of effective reagents with high affinity to the element Si is the subclinical breakthrough point of specularite/aegirite separation.

Enhanced Photoelectrocatalytic performance of α-MnO2 by Sb and N charge compensation  

2021 ◽  
Author(s):  
Min-Min Guo ◽  
Huimin Yang ◽  
Yuting Du ◽  
Yingjin Wang ◽  
Xiaojing Yang
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Performance Test ◽  
Charge Compensation ◽  
Active Area ◽  
First Principle ◽  
Photoelectrochemical Performance ◽  
Functional Theory ◽  
Principle Calculation ◽  
First Principle Calculation

The photoelectrocatalytic performance of (Sb,N)-MnO2 are explored by experiment and first principle calculation based on density functional theory. The photoelectrochemical performance test shows that 6% (Sb,N)-MnO2 with maximum electrochemical active area...

scholarly journals Electronic Structure and Optical Properties of Co and Fe Doped ZnO

2016 ◽  
Vol 43 ◽  
pp. 23-28 ◽  
Author(s):  
Chun Ping Li ◽  
Ge Gao ◽  
Xin Chen
Keyword(s):  
Density Functional Theory ◽  
Optical Properties ◽  
Electronic Structures ◽  
Density Functional ◽  
Band Gaps ◽  
First Principle ◽  
Functional Theory ◽  
Doped Zno ◽  
Pseudo Potential ◽  
Co Doped

First-principle ultrasoft pseudo potential approach of the plane wave based on density functional theory (DFT) has been used for studying the electronic characterization and optical properties of ZnO and Fe, Co doped ZnO. The results show that the doping impurities change the lattice parameters a little, but bring more changes in the electronic structures. The band gaps are broadened by doping, and the Fermi level accesses to the conduction band which will lead the system to show the character of metallic properties. The dielectric function and absorption peaks are identified and the changes compared to pure ZnO are analyzed in detail.

FIRST PRINCIPLE CALCULATION OF ELECTRONIC BAND STRUCTURE AND OPTICAL PROPERTIES OF KIO3

2009 ◽  
Vol 23 (10) ◽  
pp. 2405-2412
Author(s):  
HARUN AKKUS ◽  
BAHATTIN ERDINC
Keyword(s):  
Optical Properties ◽  
Band Structure ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Electronic Band ◽  
Principle Calculation ◽  
First Principle Calculation ◽  
Functional Methods ◽  
A Value ◽  
Direct Band

The electronic band structure and optical properties of the ferroelectric single crystal KIO 3 have been investigated using the density functional methods. The calculated band structure for KIO 3 evidences that the crystal has a direct band gap with a value of 2.83 eV. The structural optimization has been performed. The real and imaginary parts of dielectric function, energy-loss function for volume and surface, and refractive index are calculated along the crystallographic axes.

Hydrogen storage in Beryllium decorated graphene with double vacancy and porphyrin defect — A first principles study

2017 ◽  
Vol 10 (03) ◽  
pp. 1750023 ◽  
Author(s):  
M. Mahendran ◽  
B. Rekha ◽  
S. Seenithurai ◽  
R. Kodi Pandyan ◽  
S. Vinodh Kumar
Keyword(s):  
Hydrogen Storage ◽  
Bond Length ◽  
Density Functional ◽  
Vacancy Defect ◽  
Ambient Conditions ◽  
Functional Theory ◽  
Principle Calculation ◽  
First Principle Calculation ◽  
Average Binding Energy ◽  
Defective Sites

Beryllium (Be)-decorated graphene with 585 double carbon vacancy defect and nitrogen-doped porphyrin defect are investigated for hydrogen storage applications using the first principle calculation based on density functional theory. It is found that the Be atom disperses well in the defective sites of graphene and prevents clustering. For the case of Be-decorated 585 double vacancy graphene, only two H2 molecules are adsorbed via Kubas interaction with the stretched H–H bond length of 0.8 Å. In Be-decorated porphyrin defect graphene system, four H2 molecules are molecularly chemisorbed with the H–H bond length of 0.77 Å. The chemisorptions are due to the hybridization between Be-p orbital and the H-[Formula: see text] orbital. The average binding energy of H2 molecule is found to be 0.43[Formula: see text]eV/H2 which lies within the required range that can permit recycling of H2 molecules under ambient conditions.

First Principle Calculation of Li2Fe0.5Cr0.5SiO4 for Li-Ion Battery Cathode

2015 ◽  
Vol 1112 ◽  
pp. 286-289
Author(s):  
Ganjar Kurniawan Sukandi ◽  
Triati Dewi Kencana Wungu ◽  
Ferry Iskandar
Keyword(s):  
Structural Change ◽  
Phase Stability ◽  
Density Functional ◽  
Positive Sign ◽  
Initial Structure ◽  
First Principle ◽  
Generalized Gradient ◽  
Principle Calculation ◽  
First Principle Calculation ◽  
Couple Reaction

First principle calculation based on Density Functional Theory and U correction (DFT+U) is used to investigate structural change while losing Li atom, average voltage for couple reaction, phase stability, and electronic structure of Li2Fe0.5Cr0.5SiO4. In this calculation, generalized gradient approach (GGA) of Perdew-Burke-Ernzerhof (PBE) is used for exchange-correlation functional. The initial structure of Li2Fe0.5Cr0.5SiO4 is obtained from the pmn21 structure of Li2FeSiO4 and then the Fe site is substituted by 50 % of Cr. The results of calculation show that the optimized Li2Fe0.5Cr0.5SiO4 has a monoclinic structure, which has little different with Li2FeSiO4 structure. Although the delithiated system (LiFe0.5Cr0.5SiO4) is taken into consideration, the structural geometry does not change significantly. It is indicated that the presence of Cr does not affect to the property of structural change. From the density of states (DOS) analysis, the presence of Cr causes the width of band gap become decrease. Therefore, the electronic properties change from insulator to semiconductor-like behavior. Average voltage for couple reaction M+2/ M+3 of Li2Fe0.5Cr0.5SiO4 is about 3.05 V which is lower than Li2FeSiO4. Furthermore, the formation energy for Li2Fe0.5Cr0.5SiO4 and all delithiation have a relatively positive sign compared with Li2FeSiO4 that mean that they have poor phase stability than Li2FeSiO4.

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