Fermi level dependence of gas–solid oxygen defect exchange mechanism on TiO2 (110) by first-principles calculations

2020 ◽  
Vol 153 (12) ◽  
pp. 124710 ◽  
Author(s):  
Heonjae Jeong ◽  
Edmund G. Seebauer ◽  
Elif Ertekin
Keyword(s):  
Fermi Level ◽  
First Principles ◽  
Exchange Mechanism ◽  
Oxygen Defect ◽  
First Principles Calculations ◽  
Solid Oxygen

scholarly journals First-principles calculations of the epsilon phase of solid oxygen

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Le The Anh ◽  
Masahiro Wada ◽  
Hiroshi Fukui ◽  
Tsutomu Kawatsu ◽  
Toshiaki Iitaka
Keyword(s):  
First Principles ◽  
First Principles Calculations ◽  
Solid Oxygen

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.

Pressure-Induced Tunable Magnetism and Half-Metallic Stability in Co2FeGa Heusler Alloy

2013 ◽  
Vol 477-478 ◽  
pp. 1303-1306
Author(s):  
Qin Xiang Gao
Keyword(s):  
Fermi Level ◽  
First Principles ◽  
Density Functional ◽  
High Energy ◽  
First Principles Calculations ◽  
Half Metallicity ◽  
Functional Theory ◽  
Half Metallic ◽  
Heusler Compound ◽  
The Density Functional Theory

Using the first-principles calculations within the density functional theory (DFT), we have investigated the structure, magnetism and half-metallic stability of Co2FeGa Heusler compound under pressure from 0 to 50GPa. The results revel that the lattice constant is gradually shrank and total magnetic moment in per unit slightly decreased with increasing pressure, respectively. Moreover, with the increase of the pressure, the Fermi level will move towards high-energy orientation. When the pressure reaches at 30GPa the most stable half-metallicity is observed which the Fermi level is located at the middle of the spin-minority gap.

scholarly journals Assessing the role of hydrogen in Fermi-level pinning in chalcopyrite and kesterite solar absorbers from first-principles calculations

2018 ◽  
Vol 123 (16) ◽  
pp. 161408 ◽  
Author(s):  
J. B. Varley ◽  
V. Lordi ◽  
T. Ogitsu ◽  
A. Deangelis ◽  
K. Horsley ◽  
...  
Keyword(s):  
Fermi Level ◽  
First Principles ◽  
First Principles Calculations ◽  
Fermi Level Pinning ◽  
Solar Absorbers

scholarly journals Three-dimensional metallic carbon allotropes with superhardness

2021 ◽  
Vol 10 (1) ◽  
pp. 1266-1276
Author(s):  
Qingyang Fan ◽  
Heng Liu ◽  
Li Jiang ◽  
Wei Zhang ◽  
Yanxing Song ◽  
...  
Keyword(s):  
Fermi Level ◽  
Dynamic Stability ◽  
First Principles ◽  
Mechanical Stability ◽  
Three Dimensional ◽  
First Principles Calculations ◽  
Charge Densities ◽  
Carbon Allotropes

Abstract Three novel three-dimensional orthorhombic carbon phases are proposed based on first-principles calculations in this work. These phases possess dynamic stability and mechanical stability and are theoretically more favorable in energy compared to most other carbon allotropes. The hardness levels of oP-C16, oP-C20, and oP-C24 are 47.5, 49.6, and 55.3 GPa, respectively, which are greater than those of T10, T18, and O12 carbon. In addition, although oP-C16, oP-C20, and oP-C24 are metals, their ideal shear strengths are also greater than those of common metals such as Cu, Fe, and Al. Due to p y electrons crossing the Fermi level, oP-C16, oP-C20, and oP-C24 show metallicity, and their charge densities of the band decomposition suggest that all the conductive directions of oP-C16, oP-C20, and oP-C24 are exhibited along the a- and b-axis, similar to C5.

scholarly journals Half-Metallicity and Magnetism of the Quaternary Heusler Compound TiZrCoIn1−xGex from the First-Principles Calculations

2019 ◽  
Vol 9 (4) ◽  
pp. 620 ◽  
Author(s):  
Ying Chen ◽  
Shaobo Chen ◽  
Bin Wang ◽  
Bo Wu ◽  
Haishen Huang ◽  
...  
Keyword(s):  
Fermi Level ◽  
First Principles ◽  
Magnetic Moments ◽  
First Principles Calculations ◽  
Half Metallicity ◽  
Valence Electrons ◽  
The Stability ◽  
Formation Energies ◽  
Quaternary Heusler Compound ◽  
Ge Doping

The effects of doping on the electronic and magnetic properties of the quaternary Heusler alloy TiZrCoIn were investigated by first-principles calculations. Results showed that the appearance of half-metallicity and negative formation energies are associated in all of the TiZrCoIn1−xGex compounds, indicating that Ge doping at Z-site increases the stability without damaging the half-metallicity of the compounds. Formation energy gradually decreased with doping concentration, and the width of the spin-down gap increased with a change in Fermi level. TiZrCoIn0.25Ge0.75 was found to be the most stable half-metal. Its Fermi level was in the middle of the broadened gap, and a peak at the Fermi level was detected in the spin majority channel of the compound. The large gaps of the compounds were primarily dominated by the intense d-d hybridization between Ti, Zr, and Co. The substitution of In by Ge increased the number of sp valence electrons in the system and thereby enhanced RKKY exchange interaction and increased splitting. Moreover, the total spin magnetic moments of the doped compounds followed the Slater–Pauling rule of Mt = Zt − 18 and increased from 2 μB to 3 μB linearly with concentration.

Chemical Bonding and Pseudogap in Zn- and Cd-based Compounds with Complex Hexagonal Structures

2003 ◽  
Vol 805 ◽  
Author(s):  
Y. Ishii ◽  
K. Nozawa ◽  
T. Fujiwara
Keyword(s):  
Fermi Level ◽  
Density Of States ◽  
Chemical Bonding ◽  
First Principles ◽  
Electronic Structures ◽  
Unit Cell ◽  
First Principles Calculations ◽  
Electronic Density ◽  
Electronic Density Of States ◽  
Crystal Orbital

ABSTRACTElectronic structures of hexagonal Zn-Mg-Y and Cd58Y13 compounds are studied by first-principles calculations. Both of the systems show deep pseudogap in the electronic density of states near the Fermi level and considered to be stabilized electronically. To illustrate bonding nature of electronic wavefunctions, the crystal orbital Hamilton population (COHP) is calculated for neighboring pairs of atoms in the unit cell. It is found that the bonding nature is changed from bonding to anti-bonding almost exactly at the Fermi level for Zn-Zn and Cd-Cd bonds. On the contrary, for Zn/Cd-Y bonds, both of the states below and above the pseudogap behave as bonding ones. Possible effects of the p-d hybridization are discussed.

scholarly journals How dopants limit the ultrahigh thermal conductivity of boron arsenide: a first principles study

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Mauro Fava ◽  
Nakib Haider Protik ◽  
Chunhua Li ◽  
Navaneetha Krishnan Ravichandran ◽  
Jesús Carrete ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Fermi Level ◽  
First Principles ◽  
Phonon Scattering ◽  
General Trend ◽  
Group Iv ◽  
First Principles Calculations ◽  
Large Hole ◽  
Fermi Level Pinning ◽  
Design Considerations

AbstractThe promise enabled by boron arsenide’s (BAs) high thermal conductivity (κ) in power electronics cannot be assessed without taking into account the reduction incurred when doping the material. Using first principles calculations, we determine the κ reduction induced by different group IV impurities in BAs as a function of concentration and charge state. We unveil a general trend, where neutral impurities scatter phonons more strongly than the charged ones. CB and GeAs impurities show by far the weakest phonon scattering and retain BAs κ values of over ~1000 W⋅K−1⋅m−1 even at high densities. Both Si and Ge achieve large hole concentrations while maintaining high κ. Furthermore, going beyond the doping compensation threshold associated to Fermi level pinning triggers observable changes in the thermal conductivity. This informs design considerations on the doping of BAs, and it also suggests a direct way to determine the onset of compensation doping in experimental samples.

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