Insight into the surface activity of defect structure in α-MnO2 nanorod: first-principles research

AbstractThe contribution of defect structure to the catalytic property of α-MnO2 nanorod still keeps mysterious right now. Using microfacet models representing defect structure and bulk models with high Miller index, several parameters, such as cohesive energy, surface energy, density of state, electrostatic potential, et al., have been used to investigate the internal mechanism of their chemical activities by first-principles calculation. The results show that the trend in surface energies of microfacet models follows as Esurface[(112 × 211)] > Esurface[(110 × 211)] > Esurface[(100 × 211)] > Esurface[(111 × 211)] > Esurface[(112 × 112)] > Esurface[(111 × 112)], wherein all of them are larger than that of bulk models. So the chemical activity of defect structure is much more powerful than that of bulk surface. Deep researches on electronic structure show that the excellent chemical activity of microfacet structure has larger value in dipole moments and electrostatic potential than that of bulk surface layer. And the microfacet models possess much more peaks of valent electrons in deformantion electronic density and molecular orbital. Density of state indicates that the excellent chemical activity of defect structure comes from their proper hybridization in p and d orbitals.

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Theoretical Investigation on Microstructure of the Novel 24R-Type LPSO Phase in Mg97Zn1Y2 Alloy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.233-235.2359 ◽

2011 ◽

Vol 233-235 ◽

pp. 2359-2366

Author(s):

Ping Ying Tang ◽

Meng Xue Zeng ◽

Dong Lin Li ◽

Bi Yu Tang ◽

Li Ming Peng ◽

...

Keyword(s):

First Principles ◽

Density Functional ◽

Stacking Fault ◽

First Principles Calculation ◽

The Novel ◽

Ordered Structure ◽

Density Of State ◽

Electronic Density ◽

Functional Theory ◽

Long Period

The first-principles calculation based on density functional theory has been carried out to study the microstructural feature of the novel 24R-type long period stacking ordered structure in Mg97Zn1Y2alloy. The lattice positions of the Y and Zn atoms are determined theoretically, it is shown that the additive atoms are firstly enriched in the stacking fault layers at the two ends, a small amount are distributed in the interior stacking fault layers of the structure. And the arrangement of these Y and Zn atoms trends to be along the diagonal line of the unit cell. The structural stability is analyzed and the electronic density of state is discussed as well as.

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First-Principles Calculation of Conductivity of Ce-C Codoped SnO2 Contacts

Advances in Condensed Matter Physics ◽

10.1155/2021/4346979 ◽

2021 ◽

Vol 2021 ◽

pp. 1-9

Author(s):

Can Ding ◽

Zhenjiang Gao ◽

Xing Hu ◽

Zhao Yuan

Keyword(s):

Charge Density ◽

Lattice Constant ◽

First Principles ◽

Density Functional ◽

Energy Levels ◽

Circuit Breaker ◽

Enthalpy Change ◽

First Principles Calculation ◽

Contact Material ◽

Electronic Density

The contact is the core element of the vacuum interrupter of the mechanical DC circuit breaker. The electrical conductivity and welding resistance of the material directly affect its stability and reliability. AgSnO2 contact material has low resistivity, welding resistance, and so on. This material occupies an important position of the circuit breaker contact material. This research is based on the first-principles analysis method of density functional theory. The article calculated the lattice constant, enthalpy change, energy band, electronic density of state, charge density distribution, population, and conductivity of Ce, C single-doped, and Ce-C codoped SnO2 systems. The results show that Ce, C single doping, and Ce-C codoping all increase the cell volume and lattice constant. When the elements are codoped, the enthalpy change is the largest, and the thermal stability is the best. It has the smallest bandgap, the most impurity energy levels, and the least energy required for electronic transitions. The 4f orbital electrons of the Ce atom and the 2p orbital electrons of C are the sources of impurity energy near the Fermi level. When the elements are codoped, more impurity energy levels are generated at the bottom of the conduction band and the top of the valence band. Its bandgap is reduced so conductivity is improved. From the charge density and population analysis, the number of free electrons of Ce atoms and C atoms is redistributed after codoping. It forms a Ce-C covalent bond to further increase the degree of commonality of electrons and enhance the metallicity. The conductivity analysis shows that both single-doped and codoped conductivity have been improved. When the elements are codoped, the conductivity is the largest, and the conductivity is the best.

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Repairing single and double atomic vacancies in a C3N monolayer with CO or NO molecules: a first-principles study

Physical Chemistry Chemical Physics ◽

10.1039/c8cp01653d ◽

2018 ◽

Vol 20 (19) ◽

pp. 13517-13527 ◽

Cited By ~ 25

Author(s):

Dongwei Ma ◽

Jing Zhang ◽

Yanan Tang ◽

Zhaoming Fu ◽

Zongxian Yang ◽

...

Keyword(s):

Electronic Structure ◽

Magnetic Property ◽

First Principles ◽

Chemical Activity ◽

First Principles Calculation ◽

First Principles Study ◽

C And N

Using the first-principles calculation, it is found that the electronic structure, magnetic property and chemical activity of the C3N monolayer can be significantly changed by the C and N single vacancies. Thus, we explored the repairing of the C and N single vacancies in the C3N monolayer by the CO or NO molecules.

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First-principles calculation of electronic density of states and Seebeck coefficient in transition-metal-doped Si–Ge alloys

Solid State Communications ◽

10.1016/j.ssc.2020.114115 ◽

2021 ◽

Vol 323 ◽

pp. 114115

Author(s):

Ryo Yamada ◽

Akira Masago ◽

Tetsuya Fukushima ◽

Hikari Shinya ◽

Tien Quang Nguyen ◽

...

Keyword(s):

Transition Metal ◽

Seebeck Coefficient ◽

Density Of States ◽

First Principles ◽

First Principles Calculation ◽

Electronic Density ◽

Electronic Density Of States ◽

Metal Doped

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First Principles Study on the TiN/BN/TiN Interface

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.110-116.1020 ◽

2011 ◽

Vol 110-116 ◽

pp. 1020-1023 ◽

Cited By ~ 1

Author(s):

Bao Jun Wang ◽

Fei Xie ◽

Ke Jun Jia

Keyword(s):

Tensile Strength ◽

Tensile Stress ◽

First Principles ◽

Calculation Method ◽

First Principles Calculation ◽

Strain Response ◽

Ideal Strength ◽

Stress Strain ◽

Electronic Density ◽

Friedel Oscillations

To obtain a understanding of the deform mechanism and ideal strength in superhard nanocomposites nc-TiN/a-BN. we studied, using the first-principles calculation method, the geometrical stucture, the electronic density and the tensile stress-strain response of a theoretical interfacial system TiN/BN/TiN, which consists of two TiN slabs and one sandwiched BN monolayer. The calculated results show that Friedel oscillations weaken the Ti-N interplanar bonds next to the interface, where decohesion happens. A comparison with the TiN/SiN/TiN interface was done, showing that the orientation has the huger influence on the tensile strength of TiN/BN/TiN interface.

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First-principles calculation of the elastic constants, the electronic density of states and the ductility mechanism of the intermetallic compounds: YAg, YCu and YRh

Physica B Condensed Matter ◽

10.1016/j.physb.2008.07.009 ◽

2008 ◽

Vol 403 (19-20) ◽

pp. 3792-3797 ◽

Cited By ~ 33

Author(s):

Yurong Wu ◽

Wangyu Hu ◽

Shaochang Han

Keyword(s):

Intermetallic Compounds ◽

Density Of States ◽

Elastic Constants ◽

First Principles ◽

First Principles Calculation ◽

Electronic Density ◽

Electronic Density Of States

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First principles calculation of the dipole moments of small mixed Ge/Te semiconductor clusters

Small Particles and Inorganic Clusters ◽

10.1007/978-3-642-60854-4_46 ◽

1997 ◽

pp. 182-185

Author(s):

L. C. Balbás ◽

A. Rubio ◽

J. L. Martins

Keyword(s):

First Principles ◽

Dipole Moments ◽

First Principles Calculation ◽

Semiconductor Clusters

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The structural, electronic and optical properties of Au–ZnO interface structure from the first-principles calculation

Modern Physics Letters B ◽

10.1142/s0217984918501075 ◽

2018 ◽

Vol 32 (07) ◽

pp. 1850107 ◽

Cited By ~ 2

Author(s):

Jin-Rong Huo ◽

Lu Li ◽

Hai-Xia Cheng ◽

Xiao-Xu Wang ◽

Guo-Hua Zhang ◽

...

Keyword(s):

Optical Properties ◽

Density Of States ◽

First Principles ◽

Density Functional ◽

Interface Structure ◽

First Principles Calculation ◽

Total Density ◽

Electronic Density ◽

Electronic And Optical Properties ◽

Interface Structures

The interface structure, electronic and optical properties of Au–ZnO are studied using the first-principles calculation based on density functional theory (DFT). Given the interfacial distance, bonding configurations and terminated surface, we built the optimal interface structure and calculated the electronic and optical properties of the interface. The total density of states, partial electronic density of states, electric charge density and atomic populations (Mulliken) are also displayed. The results show that the electrons converge at O atoms at the interface, leading to a stronger binding of interfaces and thereby affecting the optical properties of interface structures. In addition, we present the binding energies of different interface structures. When the interface structure of Au–ZnO gets changed, furthermore, varying optical properties are exhibited.

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Oxidation Effect for the Carbon Related Defect Formation in SiC/SiO2 Interface by First Principles Calculation

Materials Science Forum ◽

10.4028/www.scientific.net/msf.897.131 ◽

2017 ◽

Vol 897 ◽

pp. 131-134 ◽

Cited By ~ 1

Author(s):

Kenta Chokawa ◽

Kenji Shiraishi

Keyword(s):

Molecular Dynamics ◽

First Principles ◽

Defect Structure ◽

Defect Formation ◽

First Principles Calculation ◽

Molecular Dynamics Calculations ◽

Central Carbon ◽

Related Defect ◽

Gap States ◽

Oxidation Effect

We used first principles molecular dynamics calculations to study the formation of defects at the 4H-SiC(0001)/SiO2 interface by thermal oxidation. O2 molecules introduced at the interface easily form the C-C-C defect structure along with the Si-O-Si structure. The central carbon atom in the C-C-C defect is three-fold coordinated and it induces mid-gap states, which correspond to the energy level of the (C2)Si defect structure, known as the dumb-bell structure.

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First-Principles Calculation of Electronic Structure of the Cu–Doped Pyrite FeS2

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.652-654.590 ◽

2013 ◽

Vol 652-654 ◽

pp. 590-593 ◽

Cited By ~ 2

Author(s):

Jian Ling Fan ◽

Sen Kai Lu

Keyword(s):

First Principles ◽

Weak Field ◽

First Principles Calculation ◽

Structure Stability ◽

First Principle ◽

Density Of State ◽

Covalent Character ◽

Bottom Part ◽

Tetrahedral Environment ◽

Pseudo Potential

Structure stability and electronic properties of Cu-doped FeS2 were studied using the first principle calculations based on plane wave pseudo-potential theory. The calculated results revealed that the band-gap Eg of Cu-doped FeS2was 0.47 eV. The valence band of the density of state (DOS) was mostly due to the Cu 3d and S p orbitals. The bottom part of conduction band was mostly due to the Fe 3d orbitals. The calculated covalent character of the Fe–S bonds gave large delocalization of the spin resulting in smaller values. The Cu, Fe and S had the spin compensated leading to configuration s0.47 p0.61d9.78, Fe s0.27p0.58d7.03, S s1.83p4.23, respectively. The tetrahedral environment of the Fe and Cu and the relatively weak field of the S2− ligand were consistent to the Fe3+ and Cu+.

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