A First Principles Study of Palladium Impurities in Silicon Carbide

2006 ◽  
Vol 45 ◽  
pp. 1969-1973 ◽  
Author(s):  
Guido Roma
Keyword(s):  
Silicon Carbide ◽  
First Principles ◽  
Density Functional ◽  
Fission Products ◽  
Kinetic Properties ◽  
Main Task ◽  
Functional Theory ◽  
And Migration ◽  
Fuel Particles ◽  
Fission Reactors

The main task of the silicon carbide layer in Triso-coated fuel particles for gas-cooled high temperature fission reactors is to retain fission products. It has been observed that some fission products, and in particular Pd, attack the SiC layer and are supposed to be responsible for corrosion of the material, which could facilitate fission products release. We used first principles calculations based on Density Functional Theory (DFT) in order to investigate the energetic, structural, and kinetic properties of Pd impurities inside SiC; we obtained solution and migration energies in pure SiC and discuss the thermodynamics of a few reactions that could possibly occur for Pd impurities in silicon carbide.

First principles analysis of oxygen vacancy formation and migration in Sr2BMoO6 (B = Mg, Co, Ni)

RSC Advances ◽  
2016 ◽  
Vol 6 (38) ◽  
pp. 31968-31975 ◽  
Author(s):  
Shuai Zhao ◽  
Liguo Gao ◽  
Chunfeng Lan ◽  
Shyam S. Pandey ◽  
Shuzi Hayase ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Oxygen Vacancy ◽  
First Principles ◽  
Density Functional ◽  
Dft Method ◽  
Double Perovskites ◽  
Functional Theory ◽  
Oxygen Vacancy Formation ◽  
The Density Functional Theory ◽  
And Migration

In this work, we present a detailed first-principles investigation on the stoichiometric and oxygen-deficient structures of double perovskites, Sr2BMoO6 (B = Mg, Co and Ni), using the density functional theory (DFT) method.

First-principles study of the effect of lanthanum on the niobium diffusion in fcc Fe

2016 ◽  
Vol 30 (23) ◽  
pp. 1650157
Author(s):  
Xueyun Gao ◽  
Huiping Ren ◽  
Chunlong Li ◽  
Haiyan Wang ◽  
Huijie Tan
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Nearest Neighbor ◽  
Transformation Process ◽  
Binding Energies ◽  
Diffusion Activation Energy ◽  
Repulsive Interaction ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
And Migration

The effect of La on the diffusion of Nb in fcc Fe has been investigated using the first-principles calculations based on the density functional theory. The binding energies of Nb–vacancy, La–vacancy and La–Nb pairs have been calculated. The interactions of Nb–vacancy and La–Nb are attractive in 1nn and 2nn configurations (nn: nearest–neighbor). La atom attracts strongly with the 1nn vacancy, but has a weakly repulsive interaction with the 2nn vacancy. We consider four different Nb jumps in the presence of La atom to investigate the Nb diffusion in terms of vacancy formation and migration energy. The results suggest that La increases the diffusion activation energy of Nb in fcc Fe matrix, and is helpful to decelerate the Nb-diffusion-involved phase transformation process.

Calculation Of Positron Characteristics In Silicon Carbide

2000 ◽  
Vol 640 ◽  
Author(s):  
Bernardo Barbiellini ◽  
Jan Kuriplach ◽  
Wolfgang Anwand ◽  
Gerhard Brauer
Keyword(s):  
Experimental Data ◽  
Density Functional Theory ◽  
Silicon Carbide ◽  
Point Defect ◽  
First Principles ◽  
Crucial Role ◽  
Density Functional ◽  
Functional Theory ◽  
Defect Identification ◽  
Core Electrons

ABSTRACTPositron affinity calculations performed by a first-principles approach based on density functional theory reveal, contrary to many other semiconductors, that free positrons and positronium atoms can escape from SiC. It is found that the treatment of the electronpositron interaction plays a crucial role when calculating the annihilation characteristics. These characteristics originating from both valence and core electrons, combined with the corresponding measurements, yield a very useful tool for surface studies and point defect identification in the bulk. Calculations will be compared with available experimental data.

First Principles Study of Surface Properties for Silicon Carbide-Derived Structures

2012 ◽  
Vol 433-440 ◽  
pp. 306-312
Author(s):  
Hong Ge Liu ◽  
Rui Jun Zhang ◽  
Hong Yan Jin ◽  
Qiu Xiang Liu
Keyword(s):  
Silicon Carbide ◽  
Surface Properties ◽  
First Principles ◽  
Density Functional ◽  
Population Analysis ◽  
Mulliken Population ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Nanoporous Surface ◽  
Pseudo Potential

Using first-principles ultra-soft pseudo-potential approach of the plane wave based on the density functional theory (DFT), we investigated the surface properties for silicon carbide-derived structure (i.e. SiCDS). The calculated results show that, movement of C and Si atoms caused by Si removal results in surface structural changing, and a nanoporous surface feature can be observed on the SiCDS surfaces when more Si atoms are removed. The mulliken population analysis indicates that the Si removal leads to the stronger chemical bonds between C–Si and the formation of new stronger chemical bands between C–C. From the density of states, as the Si removal proportion increases, C2p becomes gradually dominant in the SiCDS surface state electrons. Moreover, the Si removal leads to evidently different band gaps, indicating that the conductivity for SiCDS surface structures can be adjusted through the Si removal.

Formation and Migration Energy of Native Defects in Silicon Carbide from First Principles: An Overview

2012 ◽  
Vol 323-325 ◽  
pp. 11-18 ◽  
Author(s):  
Guido Roma ◽  
Fabien Bruneval ◽  
Li Ao Ting ◽  
Olga Natalia Bedoya Martínez ◽  
Jean Paul Crocombette
Keyword(s):  
Silicon Carbide ◽  
Density Functional ◽  
Functional Theory ◽  
Self Diffusion ◽  
Native Point Defects ◽  
Defect Reactions ◽  
Main Defect ◽  
And Migration ◽  
Kinetic Calculations ◽  
Diffusion Properties

We present here an overview of native point defects calculations in silicon carbide using Density Functional Theory, focusing on defects energetics needed to understand self-diffusion. The goal is to assess the availability of data that are necessary in order to perform kinetic calculations to predict not only diffusion properties but also the evolution of defect populations under or after irradiation. We will discuss the spread of available data, comment on the main defect reactions that should be taken into account, and mention some of the most recent promising developments.

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.

Ab-Initio Study of Boron Diffusion Retardation in Si1-xGex

2006 ◽  
Vol 912 ◽  
Author(s):  
Yonghyun Kim ◽  
Taras A. Kirichenko ◽  
Sanjay K. Banerjee ◽  
Gyeong S. Hwang
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Density Functional Theory Calculation ◽  
Boron Diffusion ◽  
Ab Initio Study ◽  
Functional Theory ◽  
Migration Barriers ◽  
And Migration ◽  
Theory Calculation ◽  
And Diffusion

AbstractWe study B diffusion in the presence of Ge by using a first principles density functional theory calculation. We investigate the relative stability and migration barriers of Si and Ge interstitials as well as binding energy and diffusion pathway of Boron-Interstitial (BI) pair comprised of Boron and Si or Ge interstitials. We find that Ge interstitials are more stable but less mobile compared to Si interstitials, leading to higher population of interstitials in the implanted Si1-xGex. However, BI pair comprised of Ge interstitial and Boron is less stable compared to Si interstitial –Boron pair and migration barrier of BI pair in presence of Ge is increased, leading to less TED.

Influence of Ti on the dissolution and migration of He in ZrCo based on first principles investigation

2019 ◽  
Vol 21 (27) ◽  
pp. 14692-14700 ◽  
Author(s):  
Qingqing Wang ◽  
Xianggang Kong ◽  
Huilei Han ◽  
Ge Sang ◽  
Guanghui Zhang ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Ab Initio ◽  
First Principles ◽  
Density Functional ◽  
State Of The Art ◽  
Functional Theory ◽  
System P ◽  
And Migration

We have performed state-of-the-art ab initio calculations based on density functional theory to study the effect of Ti on helium dissolution and migration in a dilute Ti-doped ZrCo system.

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.

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