Effect of carbon on behavior of helium in vanadium: A first-principles investigation

2018 ◽  
Vol 32 (01) ◽  
pp. 1750269
Author(s):  
Juan Hua ◽  
Ying Li ◽  
Yue-Lin Liu ◽  
Ming-Wen Zhao ◽  
Xiang-Dong Liu
Keyword(s):  
Charge Density ◽  
First Principles ◽  
Trapping Center ◽  
First Principles Calculations ◽  
Free Vacancy ◽  
He Atom

By using the first-principles calculations, we studied the effect of carbon (C) on the behaviors of helium (He) in vanadium (V). The results show that C can effectively reduce the solubility of He in bulk V. Compared with defect-free V bulk, the C-vac complex reduces the charge density around it, which makes it act as a trapping center and promotes He nucleation. The maximum number of He atoms trapped by the C-vac complex is five. Furthermore, the interaction between He and the C-vac complex is slightly stronger than that in a C-free vacancy, which indicates that C could increase the trapping ability of vacancy to He atom. Based on the above results, we conclude that C has a certain influence on the dissolution and the trapping behaviors of He in V.

scholarly journals Rich p -type-doping phenomena in boron-substituted silicene systems

2020 ◽  
Vol 7 (12) ◽  
pp. 200723
Author(s):  
Hai Duong Pham ◽  
Wu-Pei Su ◽  
Thi Dieu Hien Nguyen ◽  
Ngoc Thanh Thuy Tran ◽  
Ming-Fa Lin
Keyword(s):  
Charge Transfer ◽  
Fermi Level ◽  
Charge Density ◽  
Electronic Properties ◽  
First Principles ◽  
Chemical Environment ◽  
First Principles Calculations ◽  
Density Distributions ◽  
Essential Properties ◽  
P Type

The essential properties of monolayer silicene greatly enriched by boron substitutions are thoroughly explored through first-principles calculations. Delicate analyses are conducted on the highly non-uniform Moire superlattices, atom-dominated band structures, charge density distributions and atom- and orbital-decomposed van Hove singularities. The hybridized 2 p z –3 p z and [2s, 2 p x , 2 p y ]–[3s, 3 p x , 3 p y ] bondings, with orthogonal relations, are obtained from the developed theoretical framework. The red-shifted Fermi level and the modified Dirac cones/ π bands/ σ bands are clearly identified under various concentrations and configurations of boron-guest atoms. Our results demonstrate that the charge transfer leads to the non-uniform chemical environment that creates diverse electronic properties.

COMPARATIVE STUDY OF THE STRUCTURAL AND ELECTRONIC PROPERTIES OF BN(5, 5) AND C(5, 5) NANOTUBES UNDER PRESSURE

2010 ◽  
Vol 24 (24) ◽  
pp. 4851-4859
Author(s):  
KAIHUA HE ◽  
GUANG ZHENG ◽  
GANG CHEN ◽  
QILI CHEN ◽  
MIAO WAN ◽  
...  
Keyword(s):  
High Pressure ◽  
Comparative Study ◽  
Charge Density ◽  
Band Gap ◽  
Electronic Properties ◽  
Cross Section ◽  
First Principles ◽  
First Principles Calculations ◽  
Zinc Blende ◽  
Structural And Electronic Properties

The structural and electronic properties of BN(5, 5) and C(5, 5) nanotubes under pressure are studied by using first principles calculations. In our study range, BN(5, 5) undergoes obvious elliptical distortion, while for C(5, 5) the cross section first becomes an ellipse and then, under further pressure, is flattened. The band gap of BN(5, 5) decreases with increasing pressure, which is inverse to that of zinc blende BN, whereas for C(5, 5) the metallicity is always preserved under high pressure. The population of charge density indicates that intertube bonding is formed under pressure. We also find that BN(5, 5) may collapse, and a new polymer material based on C(5, 5) is formed by applying pressure.

Electronic properties and lattice configurations of Au/CH3NH3PbI3 interface

2017 ◽  
Vol 31 (18) ◽  
pp. 1750199 ◽  
Author(s):  
F. J. Si ◽  
W. Hu ◽  
F. L. Tang ◽  
Y. W. Cheng ◽  
H. T. Xue
Keyword(s):  
Binding Energy ◽  
Charge Density ◽  
Density Of States ◽  
First Principles ◽  
Lattice Mismatch ◽  
Lattice Structure ◽  
Electronic States ◽  
Density Difference ◽  
First Principles Calculations ◽  
Charge Density Difference

The lattice structure, interface binding energy, density of states, charge density difference and Bader charges of Au (100)/CH3NH3PbI3 (MAPbI3) (100) interface were studied with the first-principles calculations. The lattice mismatch of the Au (100)/MAPbI3 (100) interface is 3.48%. The interface binding energy is −0.124 J/m2. There is a small amount of electronic states nearby the interface through analyzing the density of states of the interface. In addition, the atom orbital has hybridizations nearby the interface. Through analyzing charge density difference and Bader charges, it is found that there is obvious charge transfer at the interface.

Vacancy induced Jahn–Teller distortion in silicon and its influence to the electronic structure

2015 ◽  
Vol 29 (24) ◽  
pp. 1550136
Author(s):  
Shuying Zhong ◽  
Xueling Lei ◽  
Lang Zhou
Keyword(s):  
Electronic Structure ◽  
Charge Density ◽  
First Principles ◽  
Electronic Structures ◽  
Crystalline Silicon ◽  
First Principles Calculations ◽  
Teller Distortion ◽  
Jahn Teller ◽  
The Difference ◽  
Jahn Teller Distortion

Atomic and electronic structures of monovacancy (V1), divacancy (V2) and ring hexavacancy (V6) in crystalline silicon are studied using first-principles calculations in periodic supercells. Our results show that the V6 defect is the most stable among V1, V2 and V6 defects, and the V2-RB structure is a little more stable than the V2-LP structure due to lower vacancy formation energy. Furthermore, it is found that both V1 and V2 undergo the Jahn–Teller (JT) distortion while V6 does not. As a result, V1 and V2 have deep levels in the gap which mainly come from the neighboring atoms to vacancy. V6 has tailing bands in the gap, and so has a more stable electronic structure than V1 and V2. In addition, the JT distortion also reflects in the band decomposed charge density and the difference charge density.

Formation of hybrid ABX3perovskite compounds for solar cell application: first-principles calculations of effective ionic radii and determination of tolerance factors

2017 ◽  
Vol 46 (11) ◽  
pp. 3500-3509 ◽  
Author(s):  
Markus Becker ◽  
Thorsten Klüner ◽  
Michael Wark
Keyword(s):  
Solar Cell ◽  
Charge Density ◽  
First Principles ◽  
First Principles Calculations ◽  
Stability Criteria ◽  
Ionic Radii ◽  
Solar Cell Application ◽  
Molecular Cations ◽  
Tolerance Factors

Stability criteria of potential ABX3perovskite compounds are calculated using charge-density dependent effective ionic radii of molecular cations.

Effect of impurity carbon and oxygen atoms on the behavior of hydrogen in vanadium in a fusion environment: A first-principles study

2018 ◽  
Vol 32 (21) ◽  
pp. 1850232
Author(s):  
Juan Hua ◽  
Ying Li ◽  
Yue-Lin Liu
Keyword(s):  
Structural Material ◽  
First Principles ◽  
Nuclear Fusion ◽  
Fusion Reactors ◽  
First Principles Calculations ◽  
Metal Interactions ◽  
First Principles Study ◽  
Free Vacancy ◽  
Oxygen Atoms

We have investigated the effect of impurity X (X = C and O) atoms on the behavior of hydrogen in vanadium, which is an ideal structural material for nuclear fusion reactors, by first-principles calculations. We found that (1) in bulk V, the interaction between an interstitial H atom and an X atom is repulsive, and the interaction with O is much stronger than that with C. (2) The X–vacancy (vac) cluster can act as a center for capturing H in V. The C-vac cluster can trap as many as two H atoms, while the O–vac cluster can capture up to four H atoms. (3) C and O impurities can effectively decrease the trapping energy of a single H atom in a vacancy. The H-trapping energies in the C–vac and O–vac complexes are 0.88 eV and 0.46 eV, respectively, both of which are lower than those in the X-free vacancy. (4) Both H–X and X-metal interactions affect the H solubility in V. The above results provide important information for application of vanadium as a structural material for nuclear fusion tokamaks.

Atomic simulations of GB sliding in pure and segregated bicrystals

2013 ◽  
Vol 1515 ◽  
Author(s):  
Motohiro Yuasa ◽  
Yasumasa Chino ◽  
Mamoru Mabuchi
Keyword(s):  
Molecular Dynamics ◽  
Electronic Structure ◽  
Grain Boundary ◽  
Charge Density ◽  
First Principles ◽  
Deformation Mode ◽  
Md Simulations ◽  
Bond Critical Point ◽  
First Principles Calculations ◽  
Atomic Simulations

ABSTRACTGrain boundary (GB) sliding is an important deformation mode in polycrystals, and it has been extensively investigated, for example, there are many studies on influences of the atomic geometry in the GB region. However, it is important to investigate GB sliding from the electronic structure of GB for deeper understandings of the sliding mechanisms. In the present work, we investigated the GBs sliding in pure and segregated bicrystals with classical molecular dynamics (MD) simulations and first-principles calculations. It is accepted that the sliding rate is affected by the GB energy. However, there was no correlation between the sliding rate and the GB energy in either the pure or the segregated bicrystals. First-principles calculations revealed that the sliding rate calculated by the MD simulations increases with decreasing minimum charge density at the bond critical point in the GB. This held in both the pure and segregated bicrystals. It seems that the sliding rate depends on atomic movement at the minimum charge density sites.

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