The Properties of a Na-Doped Twist Boundary in SrTiO3 from First Principles

2002 ◽  
Vol 751 ◽  
Author(s):  
Roope K. Astala ◽  
Paul D. Bristowe
Keyword(s):  
Electronic Structure ◽  
Grain Boundary ◽  
Plane Wave ◽  
First Principles ◽  
Driving Force ◽  
Chemical Potential ◽  
Twist Boundary ◽  
Atomic Displacements ◽  
Formation Energies ◽  
Oxygen Chemical Potential

ABSTRACTThe segregation of Nasr impurities to a Σ = 5 [001] twist boundary in SrTiO3 is studied using DFT-based plane-wave pseudopotential techniques. The formation energies of the impurities are calculated as a function of oxygen chemical potential and electron chemical potential. The results indicate a strong driving force for segregation to the boundary and that the Na impurities exhibit acceptor-like behaviour. The atomic displacements caused by the impurities are small both in the bulk and at the grain boundary. Based on the results a model is suggested in which Nasr segregation is driven by soft relaxation of the electronic structure.

First-Principles Study of π-Bonded (100) Planar Defects in Diamond

1998 ◽  
Vol 538 ◽  
Author(s):  
Peter Zapol ◽  
Larry A. Curtiss ◽  
Dieter M. Gruen
Keyword(s):  
Electronic Structure ◽  
Grain Boundary ◽  
First Principles ◽  
Density Functional ◽  
Single Point ◽  
High Energy ◽  
Dynamics Simulation ◽  
Functional Study ◽  
Planar Defects ◽  
Formation Energies

AbstractA periodic density functional study of the high-energy π-bonded (100) stacking fault in diamond that can serve as a prototype of a twist grain boundary has been carried out. Information on formation energies, geometries and the electronic structure has been obtained. A single point electronic structure calculation of a ∑5 twist grain boundary based on the geometry taken from a molecular dynamics simulation has also been performed.

scholarly journals First-principles study on the effects of N and Al doping on the mechanical properties and electronic structures of TiC

RSC Advances ◽  
2020 ◽  
Vol 10 (60) ◽  
pp. 36295-36302
Author(s):  
Zhinan Cao ◽  
Na Jin ◽  
Jinwen Ye ◽  
Xu Du ◽  
Ying Liu
Keyword(s):  
Mechanical Properties ◽  
Electronic Structure ◽  
Plane Wave ◽  
First Principles ◽  
Electronic Structures ◽  
First Principles Calculations ◽  
Al Doping ◽  
First Principles Study

First-principles calculations are carried out by DFT within the CASTEP plane wave code to investigate the mechanical properties and electronic structure of N and Al doped TiC.

Energetics and electronic structure of point defects associated with oxygen excess at a tilt boundary of ZnO

2000 ◽  
Vol 15 (10) ◽  
pp. 2167-2175 ◽  
Author(s):  
Fumiyasu Oba ◽  
Hirohiko Adachi ◽  
Isao Tanaka
Keyword(s):  
Electronic Structure ◽  
Point Defects ◽  
First Principles ◽  
Electronic States ◽  
Tilt Boundary ◽  
Oxygen Excess ◽  
Zno Varistors ◽  
Formation Energies ◽  
Defect Species ◽  
Static Lattice

The formation energies and electronic structure of zinc vacancies and oxygen interstitials at a tilt boundary of ZnO were investigated by a combination of static lattice and first-principles molecular orbital methods. For both of the defect species, the formation energies were lower than those of the bulk defects at certain sites in the grain boundary. The defects with low formation energies formed electronic states close to the top of the valence band. The interfacial electronic states observed experimentally in ZnO varistors cannot be explained solely by the point defects associated with the oxygen excess: the effects of impurities should be significant for the states.

Energetic stability, oxidation states, and electronic structure of Bi-doped NaTaO3: a first-principles hybrid functional study

2016 ◽  
Vol 18 (2) ◽  
pp. 857-865 ◽  
Author(s):  
Paul H. Joo ◽  
Maziar Behtash ◽  
Kesong Yang
Keyword(s):  
Electronic Structure ◽  
First Principles ◽  
Relative Stability ◽  
Chemical Potential ◽  
Oxidation States ◽  
Functional Study ◽  
Hybrid Functional ◽  
Energetic Stability

Hybrid functional calculations (HSE) well predict the relative stability of Bi-doped NaTaO3 as a function of Na chemical potential.

Atomic displacements at aΣ3(111)grain boundary inBaTiO3:A first-principles determination

2000 ◽  
Vol 63 (6) ◽  
Author(s):  
W. T. Geng ◽  
Yu-Jun Zhao ◽  
A. J. Freeman ◽  
B. Delley
Keyword(s):  
Grain Boundary ◽  
First Principles ◽  
Atomic Displacements

scholarly journals The Electronic Structure of Grain Boundaries in NB

1990 ◽  
Vol 209 ◽  
Author(s):  
Erik C. Sowa ◽  
A. Gonis ◽  
X. -G. Zhang
Keyword(s):  
Electronic Structure ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Multiple Scattering ◽  
First Principles ◽  
Scattering Theory ◽  
Real Space ◽  
First Principles Calculations ◽  
Densities Of States ◽  
Local Densities

ABSTRACTWe present first-principles calculations of the electronic structure of Nb grain boundaries. These are the first such calculations for a bcc metal using the real-space multiple-scattering theory (RSMST). Local densities of states near a Σ5 twist grain boundary are compared to those for bulk Nb.

First principles study of defects in solid electrolyte lithium thiophosphate Li7P3S11

2011 ◽  
Vol 1331 ◽  
Author(s):  
Ka Xiong ◽  
Weichao Wang ◽  
Roberto Longo Pazos ◽  
Kyeongjae Cho
Keyword(s):  
Electronic Structure ◽  
Solid Electrolyte ◽  
Band Gap ◽  
Electronic Properties ◽  
First Principles ◽  
Wide Band ◽  
Ion Conductivity ◽  
First Principles Calculations ◽  
Wide Band Gap ◽  
Formation Energies

ABSTRACTWe investigate the electronic structure of interstitial Li and Li vacancy in Li7P3S11 by first principles calculations. We find that Li7P3S11 is a good insulator with a wide band gap of 3.5 eV. We find that the Li vacancy and interstitial Li+ ion do not introduce states in the band gap hence they do not deteriorate the electronic properties of Li7P3S11. The calculated formation energies of Li vacancies are much larger than those of Li interstitials, indicating that the ion conductivity may arise from the migration of interstitial Li.

Study on Electronic Structure of the Ti Ion Implantation Al2O3 (0001) Surface by First Principles

2013 ◽  
Vol 634-638 ◽  
pp. 2555-2558
Author(s):  
Jie Yu ◽  
Jing Chao Chen ◽  
Wei Ye ◽  
Miao Yang
Keyword(s):  
Electronic Structure ◽  
Optical Property ◽  
Energy Level ◽  
Plane Wave ◽  
Ion Implantation ◽  
Color Center ◽  
First Principles ◽  
Calculation Result ◽  
Lattice Parameter ◽  
Result Show

The First-principles based on plane-wave pseudo-potentials methods was applied to investigate the lattice parameter, electronic structure and optical property of Al2O3 (0001 ) by Ti Ion implantation . The calculation result show that the color center is form by transfer electron between 3d of Ti ion orbit energy level and Al ion 3p orbit energy level. and the absorption peak is located at the region of 2.1eV, which located in 400nm-450nm,where corresponding to the color and the color was caused by F color center

The Structure and Stability of Twist Boundaries in SrTiO3 First Principles

2002 ◽  
Vol 718 ◽  
Author(s):  
Roope K. Astala ◽  
Paul D. Bristowe
Keyword(s):  
Grain Boundary ◽  
Experimental Observation ◽  
First Principles ◽  
Chemical Potential ◽  
Computational Method ◽  
Structure And Stability ◽  
Limits Of Stability ◽  
Twist Boundaries

AbstractA first principles density funtional computational method has been used to investigate the atomic stucture and energy of various distinct forms of the σ = 5(001) twist grain boundary in SrTiO3. The study focuses on four non-stoichiometric geometries which are all found to be stable to be the most stable. The grain boundary energies are computed as a function of TiO2 chemical potential and these define the limits of stability. The computed volume expansions are consistent with experimental observation and the in plane relaxations lower the boundary symmetry.

Cs ADSORPTION ON GaAS(001) As-RICH β2 (2×4) AND Ga-RICH (4×2) RECONSTRUCTION PHASES: A FIRST-PRINCIPLES RESEARCH

2020 ◽  
pp. 2150007
Author(s):  
XIAOHUA YU ◽  
HUIXIA SUN ◽  
GUIRONG SHAO
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Dipole Moment ◽  
Plane Wave ◽  
First Principles ◽  
Density Functional ◽  
Density Of State ◽  
Functional Theory ◽  
Text Reconstruction ◽  
The Stability

Using plane-wave ultrasoft pseudopotential method based on first-principles density functional theory (DFT), the adsorption of Cs atom on As-rich GaAs(001)[Formula: see text]([Formula: see text]) reconstruction phase and Ga-rich GaAs(001)([Formula: see text]) reconstruction phase are investigated. The adsorption energy, work function, dipole moment, ionicity, band structure and density of state (DOS) of Cs adsorbed GaAs [Formula: see text]([Formula: see text]) and ([Formula: see text]) models are calculated. The stability and electronic structure of Cs adsorbed GaAs [Formula: see text]([Formula: see text]) and ([Formula: see text]) models are compared. Result shows that [Formula: see text]([Formula: see text]) phase is stable than the ([Formula: see text]) phase and after that Cs adsorption [Formula: see text]([Formula: see text]) phase is more beneficial for photoemission.

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