Room-temperature metal-free ferromagnetism, stability, and spin transport properties in topologically fluorinated silicon carbide nanotubes

RSC Advances ◽  
2016 ◽  
Vol 6 (46) ◽  
pp. 39595-39604 ◽  
Author(s):  
Ping Lou
Keyword(s):  
Silicon Carbide ◽  
First Principles ◽  
Density Functional ◽  
Function Method ◽  
Room Temperature ◽  
Spin Transport ◽  
Md Simulations ◽  
Functional Theory ◽  
Silicon Carbide Nanotubes ◽  
Silicon Carbide Nanotube

A new topologically fluorinated armchair single-walled silicon carbide nanotube has been predicted via first principles density functional theory (DFT) and nonequilibrium Green's function method, as well as ab initio molecular dynamic (MD) simulations.

Electronic Transport Properties of Single-Walled Zigzag Silicon Carbide Nanotubes with Antisite Defects

2011 ◽  
Vol 403-408 ◽  
pp. 1130-1134
Author(s):  
Jiu Xu Song ◽  
Hong Xia Liu
Keyword(s):  
Silicon Carbide ◽  
Transport Properties ◽  
Electronic Transport ◽  
Density Functional ◽  
Exponential Relationship ◽  
Functional Theory ◽  
Electronic Transport Properties ◽  
Silicon Carbide Nanotubes ◽  
Silicon Carbide Nanotube ◽  
Antisite Defects

The electronic transport properties are the basis for investigations on silicon carbide nanotube (SiCNT), which are suitable to develop novel nanometer electronic devices. The electronic transport properties of Single-Walled (8, 0) SiCNTs with antisite defects are investigated with the method combined Non-Equilibrium Green’s function with density functional theory. Results show that the similarity on electronic transport properties of the nanotube with different defects is high. Under a bias value greater than 1.0 V, a nearly exponential relationship between the bias and the current is achieved, which originates from more orbital participating in its transport properties caused by the increase of the bias.

Electronic transport properties of silicon carbide molecular junctions: first-principles study

RSC Advances ◽  
2016 ◽  
Vol 6 (94) ◽  
pp. 91453-91462 ◽  
Author(s):  
Yi Mu ◽  
Zhao-Yi Zeng ◽  
Yan Cheng ◽  
Xiang-Rong Chen
Keyword(s):  
Density Functional Theory ◽  
Silicon Carbide ◽  
Transport Properties ◽  
Electronic Transport ◽  
First Principles ◽  
Density Functional ◽  
Function Method ◽  
Functional Theory ◽  
Electronic Transport Properties ◽  
Non Equilibrium Green’S Function

The contact geometry and electronic transport properties of a silicon carbide (SiC) molecule coupled with Au (1 0 0) electrodes are investigated by performing density functional theory plus the non-equilibrium Green's function method.

First-Principles Study of Adsorption Properties of NO2 on Boron-Doped Silicon Carbide Nanotube

2011 ◽  
Vol 675-677 ◽  
pp. 1015-1018 ◽  
Author(s):  
Rui Xue Ding ◽  
Yin Tang Yang ◽  
Jiu Xu Song
Keyword(s):  
Silicon Carbide ◽  
First Principles ◽  
Density Functional ◽  
Adsorption Properties ◽  
Potential Candidate ◽  
Functional Theory ◽  
Boron Doped ◽  
Silicon Carbide Nanotube ◽  
Gas Molecule ◽  
Doped Silicon

To explore a novel sensor to detect the presence of nitrogen dioxide (NO2), we investigate reactivity of boron-doped (B-doped) single-walled (8,0) silicon carbide nanotube (SiCNT) with NO2. Based on density functional theory, the structure and electronic properties of the B-doped SiCNT with and without the adsorption of NO2 molecule have been calculated. Results show that a stable adsorption between the nanotube and the gas molecule is formed and the conductivity of the SiCNT is improved obviously. B-doped SiCNT is expected to be a potential candidate for detecting the presence of NO2.

STRUCTURAL AND ELECTRONIC PROPERTIES OF FINITE-LENGTH SINGLE-WALLED CARBON AND SILICON CARBIDE NANOTUBES: DFT STUDY

2013 ◽  
Vol 27 (29) ◽  
pp. 1350210 ◽  
Author(s):  
IGOR K. PETRUSHENKO ◽  
NIKOLAY A. IVANOV
Keyword(s):  
Silicon Carbide ◽  
Electronic Properties ◽  
Density Functional ◽  
Energy Gap ◽  
Basis Set ◽  
Functional Theory ◽  
Single Walled Carbon ◽  
Silicon Carbide Nanotubes ◽  
Structural And Electronic Properties ◽  
Walled Carbon Nanotubes

This paper presents a systematical analysis of the structure and electronic properties of armchair single-walled carbon nanotubes (SWCNTs) as well as single-walled silicon carbide nanotubes ( SiCNTs ) by using density functional theory. The geometries of all species were optimized at the B3LYP level of theory using the SVP basis set. The different behavior of C – C bonds "parallel" and "perpendicular" to the nanotube axis has been found. The HOMO–LUMO energy gap, ionization potential, electron affinity, electronegativity and hardness of studied tubes were compared. The influence of both SWCNTs and SiCNTs lengths on their electronic properties has been analyzed.

Helicity analysis of single, double, and triple helical iodine chains inside single-walled silicon carbide nanotubes

2017 ◽  
Vol 95 (8) ◽  
pp. 731-737 ◽  
Author(s):  
Zhen Yao ◽  
Chun-Jian Liu ◽  
Yi Li ◽  
Xiao-Dan Jing ◽  
Quan Yuan
Keyword(s):  
Silicon Carbide ◽  
Density Functional ◽  
Chain Structure ◽  
Field Analysis ◽  
Helical Chain ◽  
Functional Theory ◽  
Silicon Carbide Nanotubes ◽  
Helical Angle ◽  
Force Field Analysis ◽  
Chain Interaction

The helicity of encapsulated single, double, and triple helical iodine chains inside single-walled silicon carbide nanotubes is studied using the van der Waals interaction potential and density functional theory (DFT). Our results show that the optimal radius of the helical iodine chain increases linearly with tube radius, which produces a constant separation between the encapsulated chain and tube wall. The optimal helical angle cannot be determined with a single helical chain, due to the absence of the inter-chain interaction. For the double and triple helical chains, a small optimal helical angle can be induced by a large inter-chain interaction for the same tubes or a large tube for the same chain structure. We also find that the helicity is insensitive to the tube chirality. The DFT calculation further justifies our classical force field analysis and provides a more comprehensive understanding of this helical chains configuration.

scholarly journals Thermoelectric characteristics of X$$_2$$YH$$_2$$ monolayers (X=Si, Ge; Y=P, As, Sb, Bi): a first-principles study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mohammad Ali Mohebpour ◽  
Shobair Mohammadi Mozvashi ◽  
Sahar Izadi Vishkayi ◽  
Meysam Bagheri Tagani
Keyword(s):  
Thermoelectric Materials ◽  
First Principles ◽  
Material Science ◽  
Figure Of Merit ◽  
Density Functional ◽  
Room Temperature ◽  
Boltzmann Transport Equation ◽  
Boltzmann Transport ◽  
Functional Theory ◽  
The Density Functional Theory

AbstractEver since global warming emerged as a serious issue, the development of promising thermoelectric materials has been one of the main hot topics of material science. In this work, we provide an in-depth understanding of the thermoelectric properties of X$$_2$$ 2 YH$$_2$$ 2 monolayers (X=Si, Ge; Y=P, As, Sb, Bi) using the density functional theory combined with the Boltzmann transport equation. The results indicate that the monolayers have very low lattice thermal conductivities in the range of 0.09−0.27 Wm$$^{-1}$$ - 1 K$$^{-1}$$ - 1 at room temperature, which are correlated with the atomic masses of primitive cells. Ge$$_2$$ 2 PH$$_2$$ 2 and Si$$_2$$ 2 SbH$$_2$$ 2 possess the highest mobilities for hole (1894 cm$$^2$$ 2 V$$^{-1}$$ - 1 s$$^{-1}$$ - 1 ) and electron (1629 cm$$^2$$ 2 V$$^{-1}$$ - 1 s$$^{-1}$$ - 1 ), respectively. Si$$_2$$ 2 BiH$$_2$$ 2 shows the largest room-temperature figure of merit, $$ZT=2.85$$ Z T = 2.85 in the n-type doping ( $$\sim 3\times 10^{12}$$ ∼ 3 × 10 12  cm$$^{-2}$$ - 2 ), which is predicted to reach 3.49 at 800 K. Additionally, Si$$_2$$ 2 SbH$$_2$$ 2 and Si$$_2$$ 2 AsH$$_2$$ 2 are found to have considerable ZT values above 2 at room temperature. Our findings suggest that the mentioned monolayers are more efficient than the traditional thermoelectric materials such as Bi$$_2$$ 2 Te$$_3$$ 3 and stimulate experimental efforts for novel syntheses and applications.

scholarly journals Phase Stability in U-6Nb Alloy Doped with Ti from the First Principles Theory

2020 ◽  
Vol 10 (10) ◽  
pp. 3417
Author(s):  
Alexander Landa ◽  
Per Söderlind ◽  
Amanda Wu
Keyword(s):  
Phase Stability ◽  
First Principles ◽  
Density Functional ◽  
Room Temperature ◽  
Rapid Quenching ◽  
Quantum Mechanical ◽  
First Principles Calculations ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Effect Of Impurities

First-principles calculations within the density-functional-theory (DFT) approach are conducted in order to explore and explain the effect of small amounts of titanium on phase stability in the U-6Nb alloy. During rapid quenching from high to room temperature, metastable phases α′ (orthorhombic), α″ (monoclinic), and γ0 (tetragonal) can form, depending on Nb concentration. Important mechanical properties depend on the crystal structure and, therefore, an understanding of the effect of impurities on phase stability is essential. Insights on this issue are obtained from quantum-mechanical DFT calculations. The DFT framework does not rely on any material-specific assumptions and is therefore ideal for an unbiased investigation of the U-Nb system.

Electronic Structures of Vacancy Defective Chiral (6,2) SiC Nanotubes

2017 ◽  
Vol 896 ◽  
pp. 3-8
Author(s):  
Ke Jian Li ◽  
Hong Xia Liu
Keyword(s):  
Density Functional Theory ◽  
Silicon Carbide ◽  
Electronic Structures ◽  
Density Functional ◽  
First Principle ◽  
Defect Level ◽  
Functional Theory ◽  
Vacancy Defects ◽  
First Principle Calculations ◽  
Silicon Carbide Nanotubes

Vacancy defects are common defects formed in the syntheses of silicon carbide nanotubes (SiCNTs) and seriously impact the electronic structures of the nanotubes. With first-principle calculations based on density functional theory (DFT), vacancy defective (6,2) SiCNTs are studied. Vacancies form a pair of fivefold and ninefold rings. Carbon vacancy introduces an occupied defect level near the top of the valence band and an unoccupied level in the conduction band. Three defect levels are found in the band gap of the SiCNT with a silicon vacancy. These results are helpful for investigations on SiCNT devices and sensors.

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