scholarly journals A first-principles understanding of point defects and impurities in GaN

2021 ◽  
Vol 129 (11) ◽  
pp. 111101
Author(s):  
John L. Lyons ◽  
Darshana Wickramaratne ◽  
Chris G. Van de Walle
Keyword(s):  
Point Defects ◽  
First Principles ◽  
Defects And Impurities

scholarly journals Insight into point defects and impurities in titanium from first principles

2018 ◽  
Vol 4 (1) ◽  
Author(s):  
Sanjeev K. Nayak ◽  
Cain J. Hung ◽  
Vinit Sharma ◽  
S. Pamir Alpay ◽  
Avinash M. Dongare ◽  
...  
Keyword(s):  
Point Defects ◽  
First Principles ◽  
Defects And Impurities ◽  
Insight Into

First principles studies of point defects and impurities in cubic boron nitride

1998 ◽  
Vol 51 (1-3) ◽  
pp. 53-57 ◽  
Author(s):  
J.L.P Castineira ◽  
J.R Leite ◽  
L.M.R Scolfaro ◽  
R Enderlein ◽  
J.L.A Alves ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Point Defects ◽  
First Principles ◽  
Cubic Boron Nitride ◽  
Defects And Impurities

scholarly journals First Principles Calculations of Defects in Unstable Crystals: Austenitic Iron

2011 ◽  
Vol 1363 ◽  
Author(s):  
G.J. Ackland ◽  
T.P.C. Klaver ◽  
D.J. Hepburn
Keyword(s):  
Point Defects ◽  
First Principles ◽  
Defect Formation ◽  
Single Layer ◽  
Temperature Limit ◽  
Reference State ◽  
First Principles Calculations ◽  
General Picture ◽  
Bcc Iron ◽  
Defect Energies

ABSTRACTFirst principles calculations have given a new insight into the energies of point defects in many different materials, information which cannot be readily obtained from experiment. Most such calculations are done at zero Kelvin, with the assumption that finite temperature effects on defect energies and barriers are small. In some materials, however, the stable crystal structure of interest is mechanically unstable at 0K. In such cases, alternate approaches are needed. Here we present results of first principles calculations of austenitic iron using the VASP code. We determine an appropriate reference state for collinear magnetism to be the antiferromagnetic (001) double-layer (AFM-d) which is both stable and lower in energy than other possible models for the low temperature limit of paramagnetic fcc iron. Another plausible reference state is the antiferromagnetic (001) single layer (AFM-1). We then consider the energetics of dissolving typical alloying impurities (Ni, Cr) in the materials, and their interaction with point defects typical of the irradiated environment. We show that the calculated defect formation energies have fairly high dependence on the reference state chosen: in some cases this is due to instability of the reference state, a problem which does not seem to apply to AFM-d and AFM-1. Furthermore, there is a correlation between local free volume magnetism and energetics. Despite this, a general picture emerge that point defects in austenitic iron have geometries similar to those in simpler, non-magnetic, thermodynamically stable FCC metals. The defect energies are similar to those in BCC iron. The effect of substitutional Ni and Cr on defect properties is weak, rarely more than tenths of eV, so it is unlikely that small amounts of Ni and Cr will have a significant effect on the radiation damage in austenitic iron at high temperatures.

Advances in first-principles modelling of point defects in UO2: f electron correlations and the issue of local energy minima

2013 ◽  
Vol 25 (33) ◽  
pp. 333201 ◽  
Author(s):  
B Dorado ◽  
M Freyss ◽  
B Amadon ◽  
M Bertolus ◽  
G Jomard ◽  
...  
Keyword(s):  
Point Defects ◽  
First Principles ◽  
Local Energy ◽  
Electron Correlations

scholarly journals Effect of point defects on the electronic density states of SnC nanosheets: First-principles calculations

2017 ◽  
Vol 7 ◽  
pp. 3209-3215 ◽  
Author(s):  
Soleyman Majidi ◽  
Amine Achour ◽  
D.P. Rai ◽  
Payman Nayebi ◽  
Shahram Solaymani ◽  
...  
Keyword(s):  
Point Defects ◽  
First Principles ◽  
First Principles Calculations ◽  
Electronic Density

scholarly journals First-Principles Assessment of the Structure and Stability of 15 Intrinsic Point Defects in Zinc-Blende Indium Arsenide

Crystals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 48 ◽  
Author(s):  
Qing Peng ◽  
Nanjun Chen ◽  
Danhong Huang ◽  
Eric Heller ◽  
David Cardimona ◽  
...  
Keyword(s):  
Fermi Level ◽  
Charge State ◽  
Indium Arsenide ◽  
Point Defects ◽  
First Principles ◽  
Formation Energy ◽  
Fast Diffusion ◽  
Intrinsic Point Defects ◽  
Zinc Blende ◽  
Tetrahedral Sites

Point defects are inevitable, at least due to thermodynamics, and essential for engineering semiconductors. Herein, we investigate the formation and electronic structures of fifteen different kinds of intrinsic point defects of zinc blende indium arsenide (zb-InAs ) using first-principles calculations. For As-rich environment, substitutional point defects are the primary intrinsic point defects in zb-InAs until the n-type doping region with Fermi level above 0.32 eV is reached, where the dominant intrinsic point defects are changed to In vacancies. For In-rich environment, In tetrahedral interstitial has the lowest formation energy till n-type doped region with Fermi level 0.24 eV where substitutional point defects In A s take over. The dumbbell interstitials prefer < 110 > configurations. For tetrahedral interstitials, In atoms prefer 4-As tetrahedral site for both As-rich and In-rich environments until the Fermi level goes above 0.26 eV in n-type doped region, where In atoms acquire the same formation energy at both tetrahedral sites and the same charge state. This implies a fast diffusion along the t − T − t path among the tetrahedral sites for In atoms. The In vacancies V I n decrease quickly and monotonically with increasing Fermi level and has a q = − 3 e charge state at the same time. The most popular vacancy-type defect is V I n in an As-rich environment, but switches to V A s in an In-rich environment at light p-doped region when Fermi level below 0.2 eV. This study sheds light on the relative stabilities of these intrinsic point defects, their concentrations and possible diffusions, which is expected useful in defect-engineering zb-InAs based semiconductors, as well as the material design for radiation-tolerant electronics.

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