First-principles calculation of defect formation energy in chalcopyrite-type CuInSe2, CuGaSe2 and CuAlSe2

2005 ◽  
Vol 66 (11) ◽  
pp. 1924-1927 ◽  
Author(s):  
Tsuyoshi Maeda ◽  
Takahiro Wada
Keyword(s):  
First Principles ◽  
Formation Energy ◽  
Defect Formation ◽  
First Principles Calculation ◽  
Defect Formation Energy

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.

First-Principles Calculation of Defect Formation and Positron Annihilation States in Bi2Te3

2017 ◽  
Vol 373 ◽  
pp. 41-45 ◽  
Author(s):  
Bin Zhao ◽  
Bo Zhou ◽  
Chong Yang Li ◽  
Ning Qi ◽  
Zhi Quan Chen
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Formation Energy ◽  
Defect Formation ◽  
First Principles Calculation ◽  
Functional Theory ◽  
Rich Condition ◽  
The Density Functional Theory ◽  
Positron Wave Function ◽  
Positron Lifetimes

Defect formation energy in Bi2Te3 thermoelectric material was calculated using a first principles approach based on the Density Functional Theory (DFT). For vacancy-type defect, the Te1 vacancy (VTe1) is the most stable defect with low formation energy in both Bi-rich and Te-rich conditions, which indicates that the Te1 vacancies have higher probability to be formed. For antisite defects, the formation energy of BiTe1 is much lower than that of BiTe2 in Bi-rich condition, while in Te-rich condition it is beneficial for TeBi with lower formation energy. Positron wave function distribution and positron lifetimes of different annihilation states in Bi2Te3 were also calculated using the atomic superposition (ATSUP) method. The positron bulk lifetime in Bi2Te3 is about 231 ps, and for the neutral vacancy-type defects without relaxation, the positron lifetimes of VBi, VTe1 and VTe2 are 275 ps, 295 ps and 269 ps, respectively.

Tuning magnetism by biaxial strain in native ZnO

2015 ◽  
Vol 17 (25) ◽  
pp. 16536-16544 ◽  
Author(s):  
Chengxiao Peng ◽  
Yuanxu Wang ◽  
Zhenxiang Cheng ◽  
Guangbiao Zhang ◽  
Chao Wang ◽  
...  
Keyword(s):  
Formation Energy ◽  
Defect Formation ◽  
Biaxial Strain ◽  
Defect Formation Energy

Strain conditions have little effect on the defect formation energy of Zn and O vacancies in ZnO, but they do affect the magnetism significantly.

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