Kinetics of Frenkel Defect Formation in TiO2 from First Principles

2013 ◽  
Vol 1561 ◽  
Author(s):  
Sergey V. Barabash ◽  
Charlene Chen ◽  
Dipu Pramanik ◽  
Blanka Magyari-Köpe ◽  
Yoshio Nishi
Keyword(s):  
First Principles ◽  
Defect Formation ◽  
Elastic Band ◽  
Unusual Behavior ◽  
Interstitial Position ◽  
Frenkel Defect ◽  
Electrical Stress ◽  
Band Method ◽  
Stress Damage ◽  
Annealing Experiments

ABSTRACTMotivated by the unusual behavior of TiO2 films seen in electrical stress and defect annealing experiments, we studied the energy profile for forming a Frenkel defect in rutile TiO2, using first-principles calculations with a nudged-elastic-band method. We found strongly asymmetric diffusion barriers. The Frenkel pairs with small separation are exceedingly short-lived: the Ti interstitial position nearest to the the Ti vacancy is separated by only a 0.15eV barrier, and the next-nearest interstitial position is dynamically unstable. The formation enthalpies of Frenkel pairs with larger separation gradually vary between 4.2 and 5.0 eV, separated by 0.3-0.4eV barriers along the (001) direction. Contrary to some previous studies, we do not find Frenkel configurations with tetrahedrally bonded Ti interstitials. The very low barriers for Frenkel defect evolution are consistent with the observations from the electrical stress damage annealing experiments.

Vacancy Migration Barrier Energetics and Pathways in Silica

1998 ◽  
Vol 538 ◽  
Author(s):  
L. R. Corrales ◽  
R.M. Van Ginhoven ◽  
J. Song ◽  
H. Jónsson
Keyword(s):  
Point Defect ◽  
Defect Formation ◽  
Vacancy Defect ◽  
Elastic Band ◽  
Simulation Methodology ◽  
Defect Migration ◽  
Migration Pathway ◽  
Empirical Potentials ◽  
Band Method ◽  
Migration Pathways

AbstractA study of vacancy defect migration pathways and energetics in a-quartz is carried out using an empirical simulation methodology that is coupled with the nudged elastic band method. Results from this study indicate that the migration pathway for migration is between adjacent sites. We anticipate the results will guide modifications to empirical potentials for use in the study of point defect formation of more complex systems.

scholarly journals First-principles study of the effect of dopants (Pd, Ni) on the formation and desorption of T2O from a Li2TiO3 (001) surface

RSC Advances ◽  
2019 ◽  
Vol 9 (15) ◽  
pp. 8490-8497 ◽  
Author(s):  
Yiyu Fang ◽  
Xianggang Kong ◽  
You Yu ◽  
Xiaotong Zhang ◽  
Xiaojun Chen ◽  
...  
Keyword(s):  
First Principles ◽  
Tritiated Water ◽  
First Principles Calculations ◽  
Elastic Band ◽  
First Principles Study ◽  
Band Method ◽  
Effect Of Pd

We investigated the effect of Pd and Ni dopants on the formation and desorption of tritiated water (T2O) molecules from the Li2TiO3 (001) surface using first-principles calculations coupled with the climbing-image nudged elastic band method.

scholarly journals Effects of Mo alloying on stability and diffusion of hydrogen in the Nb16H phase: a first-principles investigation

RSC Advances ◽  
2019 ◽  
Vol 9 (34) ◽  
pp. 19495-19500 ◽  
Author(s):  
Dianhui Wang ◽  
Yang Wu ◽  
Zhenzhen Wan ◽  
Feng Wang ◽  
Zhongmin Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Structural Stability ◽  
First Principles ◽  
Hydrogen Diffusion ◽  
First Principles Calculations ◽  
Elastic Band ◽  
Diffusion Behavior ◽  
Band Method ◽  
And Diffusion ◽  
Diffusion Of Hydrogen

First-principles calculations and climbing-image nudged elastic band method were used to investigate the effects of Mo alloying on the structural stability, mechanical properties, and hydrogen-diffusion behavior of Nb.

The Role of Na and Mg Doping on the Electronic Conductivity of LiFePO4 : First-Principles Investigations

2012 ◽  
Vol 629 ◽  
pp. 64-69
Author(s):  
Jing Wu ◽  
Gui Gui Xu ◽  
Ying Bin Lin ◽  
Zhi Gao Huang
Keyword(s):  
Activation Energy ◽  
First Principles ◽  
Electronic Conductivity ◽  
Impurity Level ◽  
Narrow Gap ◽  
Elastic Band ◽  
Band Method ◽  
Calculated Activation ◽  
Mg Doped

The effects of Na and Mg doped Li site for Li1-xMxFePO4 have been studied using first-principles within GGA+U. Elastic band method has been used to calculate the activation energy for Li diffusion. The calculated results mean that, the band gaps of the Na and Mg doped Li1-xMxFePO4 are both narrow than that of the un-doped. Especially Mg dopant gives rise to much narrow gap, which is attributed to the appearance of impurity level in the forbidden band of un-doped LiFePO4. The calculated activation energies for LiFePO4, Li0.875Na0.125Subscript textFePO4, and Li0.875Mg0.125FePO4 are 0.33eV, 0.31 eV, and 0.15 eV, respectively. From the calculated results of band gap and activation energy, we can find that Mg dopant will benefit for the hopping of electrons and the improvement of the electronic conductivity for LiFePO4.

First-Principles Study of Reaction Process of SiC and HF Molecules in Catalyst-Referred Etching

2012 ◽  
Vol 523-524 ◽  
pp. 173-177 ◽  
Author(s):  
Pho Van Bui ◽  
Kouji Inagaki ◽  
Yasuhisa Sano ◽  
Kazuto Yamauchi ◽  
Yoshitada Morikawa
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Pt Catalyst ◽  
Care Process ◽  
Generalized Gradient ◽  
Elastic Band ◽  
Functional Theory ◽  
Barrier Heights ◽  
The Density Functional Theory ◽  
Band Method

We have developed a novel abrasive-free planarization method, which we term catalyst-referred etching (CARE). In SiC CARE, Pt is used as a catalyst and HF solution is used as an etchant. CARE produces a crystallographically undamaged and smooth SiC surface. To understand the removal mechanism at the topmost surface of SiC in the CARE process, we performed first-principles reaction path simulations using the Simulation Tool for Atom Technology (STATE) program package. These calculations are based on the density functional theory within the generalized gradient approximation of Perdew et al. The barrier height is evaluated by the climbing image nudged elastic band method. We present simulation results for the initial stages of the etching process. The reaction barrier heights for the adsorption of HF molecules on the first, second, and third Si–C bonds at the edge of the topmost Si-face are 1.8, 1.9, and 1.2 eV, respectively. These barrier heights are reasonably small for a consideration of effect of the Pt catalyst.

FIRST PRINCIPLES ANALYSIS ON HYDROGEN HOPPING IN LaNi5

2009 ◽  
Vol 08 (01n02) ◽  
pp. 49-52 ◽  
Author(s):  
AKINORI TEZUKA ◽  
HAO WANG ◽  
HIROSHI OGAWA ◽  
TAMIO IKESHOJI
Keyword(s):  
Activation Energy ◽  
Potential Energy ◽  
First Principles ◽  
First Principles Calculation ◽  
Elastic Band ◽  
Band Method ◽  
Atom Position

First principles calculation is performed in order to analyze hydrogen hopping between sites in LaNi 5. Potential energy map for hydrogen is calculated on the plane which contains hydrogen sites 6m, 12o, and 4h. Applying nudged elastic band method to 12o–12n′ hopping, its hopping path and activation energy are determined. The effect of Ni atom position relaxation is discussed.

scholarly journals Correction: Intrinsic defect formation and the effect of transition metal doping on transport properties in a ductile thermoelectric material α-Ag2S: a first-principles study

2021 ◽  
Author(s):  
Ho Ngoc Nam ◽  
Ryo Yamada ◽  
Haruki Okumura ◽  
Tien Quang Nguyen ◽  
Katsuhiro Suzuki ◽  
...  
Keyword(s):  
Transition Metal ◽  
Transport Properties ◽  
Thermoelectric Material ◽  
First Principles ◽  
Defect Formation ◽  
Chem Phys ◽  
Intrinsic Defect ◽  
Transition Metal Doping ◽  
Metal Doping ◽  
First Principles Study

Correction for ‘Intrinsic defect formation and the effect of transition metal doping on transport properties in a ductile thermoelectric material α-Ag2S: a first-principles study’ by Ho Ngoc Nam et al., Phys. Chem. Chem. Phys., 2021, DOI: 10.1039/d0cp06624a.

scholarly journals Ab Initio Investigation of Helium Mobility in La2Zr2O7 Pyrochlore

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 667
Author(s):  
Yanxia Lu ◽  
Qing Peng ◽  
Chenguang Liu
Keyword(s):  
Nuclear Waste ◽  
Density Functional ◽  
Minimum Energy ◽  
Elastic Band ◽  
Waste Forms ◽  
Band Method ◽  
And Migration ◽  
High Level ◽  
Migration Pathways ◽  
Nuclear Waste Forms

The α-decay of incorporated actinides continuously produces helium, resulting in helium accumulation and causing security concerns for nuclear waste forms. The helium mobility is a key issue affecting the accumulation and kinetics of helium. The energy barriers and migration pathways of helium in a potential high-level nuclear waste forms, La2Zr2O7 pyrochlore, have been investigated in this work using the climbing image nudged elastic band method with density functional theory. The minimum energy pathway for helium to migrate in La2Zr2O7 is identified as via La–La interstitial sites with a barrier of 0.46 eV. This work may offer a theoretical foundation for further prospective studies of nuclear waste forms.

Nudged Elastic Band Method for Molecular Reactions Using Energy-Weighted Springs Combined with Eigenvector Following

2021 ◽  
Author(s):  
Vilhjálmur Ásgeirsson ◽  
Benedikt Orri Birgisson ◽  
Ragnar Bjornsson ◽  
Ute Becker ◽  
Frank Neese ◽  
...  
Keyword(s):  
Elastic Band ◽  
Band Method ◽  
Molecular Reactions
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