First-principles calculation of defect-formation energies in theY2(Ti,Sn,Zr)2O7pyrochlore

2004 ◽  
Vol 70 (5) ◽  
Author(s):  
Wendy R. Panero ◽  
Lars Stixrude ◽  
Rodney C. Ewing
Keyword(s):  
First Principles ◽  
Defect Formation ◽  
First Principles Calculation ◽  
Formation Energies

First-principles calculation of structural and energetic properties for A2Ti2O7 (A = Lu, Er, Y, Gd, Sm, Nd, La)

2009 ◽  
Vol 24 (4) ◽  
pp. 1335-1341 ◽  
Author(s):  
Z.L. Zhang ◽  
H.Y. Xiao ◽  
X.T. Zu ◽  
Fei Gao ◽  
W.J. Weber
Keyword(s):  
First Principles ◽  
Radiation Resistance ◽  
Formation Energy ◽  
Defect Formation ◽  
Band Gaps ◽  
First Principles Calculation ◽  
Energetic Properties ◽  
Cation Radius ◽  
A Site ◽  
Formation Energies

A first-principles method was used to investigate the structural and energetic properties for A2Ti2O7 (A = Lu, Er, Y, Gd, Sm, Nd, La), including the formation energies of the cation antisite-pair, the anion Frenkel pair that defines anion-disorder, and the coupled cation antisite-pair/anion-Frenkel. It is proposed that the 〈A–O48f〉 interaction may have more significant influence on the radiation resistance behavior of titanate pyrochlores, although the 〈Ti–O48f〉 interactions are relatively stronger than the 〈A–O48f〉 interactions. It was found that the defect formation energies are not simple functions of the A-site cation radii. The formation energy of the cation antisite-pair increases continuously as the A-site cation varies from Lu to Gd, and then decreases continuously with the variation of the A-site cation from Gd to La, in excellent agreement with the radiation-resistance trend of the titanate pyrochlores. The band gaps in these pyrochlores were also measured, and the band gap widths changed continuously with cation radius.

New Pt-based Superalloy System Designed from First Principles

2008 ◽  
Vol 1128 ◽  
Author(s):  
Vsevolod I. Razumovskiy ◽  
Eyvaz I. Isaev ◽  
Andrei V. Ruban ◽  
Pavel A. Korzhavyi
Keyword(s):  
Elastic Properties ◽  
First Principles ◽  
Defect Formation ◽  
Alloy System ◽  
First Principles Calculations ◽  
Phonon Spectra ◽  
Ultrahigh Temperature ◽  
New Generation ◽  
Formation Energies ◽  
Temperature Applications

AbstractPt-Sc alloys with the γ-γ′ microstructure are proposed as a basis for a new generation of Pt-based superalloys for ultrahigh-temperature applications. This alloy system was identified on the basis of first-principles calculations. Here we discuss the prospects of the Pt-Sc alloy system on the basis of calculated elastic properties, phonon spectra, and defect formation energies.

First Principles Study of Point Defects in Uranium Dioxide

2007 ◽  
Vol 561-565 ◽  
pp. 1971-1974 ◽  
Author(s):  
Ying Chen ◽  
Misako Iwasawa ◽  
Yasunori Kaneta ◽  
Toshiharu Ohnuma ◽  
Hua Yun Geng ◽  
...  
Keyword(s):  
Point Defects ◽  
First Principles ◽  
Defect Formation ◽  
Lattice Relaxation ◽  
Atomic Displacement ◽  
Grain Structure ◽  
First Principles Calculations ◽  
Fine Grain ◽  
Unit Cells ◽  
Formation Energies

To clarify the origin of a characteristic fine grain structure formed under the high burn-up of the nuclear fuel, the comprehensive first-principles calculations for UO2 containing various types of point defect have been performed by the PAW-GGA+U with lattice relaxation for supercells containing 1, 2 and 8 unit cells of UO2. The electronic structure, the atomic displacement and the defect formation energies of defective systems are obtained, and the effects of supercell size on these properties are discussed. Based on this relatively high precise self-consistent formation energies dataset, thermodynamic properties of various types of point defects in UO2 are further investigated in the framework of the point defects model.

Formation of Vacancies and Divacancies in Plane-Stressed Silicon

2005 ◽  
Vol 108-109 ◽  
pp. 433-438 ◽  
Author(s):  
S. Nicolaysen ◽  
Mariya G. Ganchenkova ◽  
Risto M. Nieminen
Keyword(s):  
Band Structure ◽  
Fermi Level ◽  
Plane Stress ◽  
First Principles ◽  
Defect Formation ◽  
Lattice Relaxation ◽  
Structure Modification ◽  
Strain Magnitude ◽  
Formation Energies ◽  
Elastic Lattice

The effect of compressive and tensile plane-stress loading on formation energies and electronic properties of vacancies and divacancies in silicon are studied by first-principles approach for in-plane strains up to 0.7%. It is demonstrated that contributions to defect formation energies from the elastic lattice relaxation and from the band structure modification respond to stress in a different manner, leading to noticeable different behaviour of formation energies for different charges states. The most stable vacancy charge states at different Fermi level are shown to be sensitive to strain magnitude and sign. This results in the strain-induced shifts and even disappearance of some of thermal ionization levels of vacancies and divacancies in the band gap.

scholarly journals Critical Thermodynamic Conditions for the Formation of p-Type β-Ga2O3 with Cu Doping

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5161
Author(s):  
Chuanyu Zhang ◽  
Zhibing Li ◽  
Weiliang Wang
Keyword(s):  
Oxygen Partial Pressure ◽  
First Principles ◽  
Electronic Structures ◽  
First Principles Calculation ◽  
Third Generation ◽  
Cu Doping ◽  
Thermodynamic Conditions ◽  
The Stability ◽  
P Type ◽  
Formation Energies

As a promising third-generation semiconductor, β-Ga2O3 is facing bottleneck for its p-type doping. We investigated the electronic structures and the stability of various Cu doped structures of β-Ga2O3. We found that Cu atoms substituting Ga atoms result in p-type conductivity. We derived the temperature and absolute oxygen partial pressure dependent formation energies of various doped structures based on first principles calculation with dipole correction. Then, the critical thermodynamic condition for forming the abovementioned substitutional structure was obtained.

scholarly journals First-principles calculation on the formation energies oflithium insertion in In Sb

2003 ◽  
Vol 52 (7) ◽  
pp. 1732
Author(s):  
Liu Hui-Ying ◽  
Hou Zhu-Feng ◽  
Zhu Zi-Ｚhong ◽  
Huang Mei-Ｃhun ◽  
Yang Yong
Keyword(s):  
First Principles ◽  
First Principles Calculation ◽  
Formation Energies

scholarly journals First-principles calculation of the vacancy formation energies in LiAl

2003 ◽  
Vol 52 (9) ◽  
pp. 2229
Author(s):  
Chen Li-Juan ◽  
Hou Zhu-Feng ◽  
Zhu Zi-Zhong ◽  
Yang Yong
Keyword(s):  
First Principles ◽  
First Principles Calculation ◽  
Vacancy Formation ◽  
Formation Energies
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