Inversion domain boundaries in ZnO: First-principles total-energy calculations

2004 ◽  
Vol 69 (8) ◽  
Author(s):  
Yanfa Yan ◽  
M. M. Al-Jassim
Keyword(s):  
Total Energy ◽  
First Principles ◽  
Energy Calculations ◽  
Inversion Domain ◽  
Domain Boundaries ◽  
Inversion Domain Boundaries

Structure and Properties of Inversion Domain Boundaries in β-Sic

1989 ◽  
Vol 159 ◽  
Author(s):  
W. R. L. Lambrecht ◽  
C. H. Lee ◽  
B. Segall
Keyword(s):  
Total Energy ◽  
Electronic Properties ◽  
Localized States ◽  
Diamond Structure ◽  
Structure And Properties ◽  
Inversion Domain ◽  
Domain Boundaries ◽  
Inversion Domain Boundaries ◽  
Energy Of Formation ◽  
The Ideal

ABSTRACTThe structure of inversion domain boundaries in β-SiC (i.e. boundaries between domains with inverted Si and C positions) is investigated by means of a Keating model. For the (110) boundary, the relaxation of the C-C and Si-Si bonds towards the ideal bond lengths which occur in the diamond structure can basically be achieved by a rotation of neighboring Si-C bonds. For the (001) boundary, it is achieved by varying the spacing between the domains. The electronic properties and total energy of formation of the relaxed (110) boundary are studied by means of linear muffin-tin orbital calculations. The interface localized states in the semiconducting gap are mainly due to the Si-Si bonds and lead to a semimetallic situation near the interface.

Migration of Aluminum Atoms in the Transformation of γ–to θ–Alumina

2002 ◽  
Vol 731 ◽  
Author(s):  
Shu-Hui Cai ◽  
Karl Sohlberg
Keyword(s):  
Aluminum Oxide ◽  
Total Energy ◽  
First Principles ◽  
Conversion Rate ◽  
Metastable Phases ◽  
Thermal Dehydration ◽  
First Principles Calculations ◽  
Energy Calculations ◽  
Domain Boundaries ◽  
Transformation Pathways

Abstractγ– and θ–alumina are two metastable phases of aluminum oxide observed along the thermal dehydration sequence of boehmite before conversion to the final product α–alumina. The transformation from γ– to θ–alumina was studied by using Al16O24 cells. Motion of some Al atoms from their γalumina positions to new positions and no O motions result in an approximate structure that, upon relaxation by first-principles calculations, becomes the known θ–alumina structure. Total-energy calculations along the paths of the atomic motions have been used to map out transformation pathways. The model accurately predicts experimentally observed domain boundaries in θ–alumina and the γ– to θ–alumina conversion rate.

scholarly journals Inversion domain boundaries in wurtzite GaN

2021 ◽  
Vol 103 (16) ◽  
Author(s):  
M. M. F. Umar ◽  
Jorge O. Sofo
Keyword(s):  
Inversion Domain ◽  
Domain Boundaries ◽  
Inversion Domain Boundaries

Interaction Between Basal Stacking Faults and Prismatic Inversion Domain Boundaries in GaN

2000 ◽  
Vol 639 ◽  
Author(s):  
Philomela Komninou ◽  
Joseph Kioseoglou ◽  
Eirini Sarigiannidou ◽  
George P. Dimitrakopulos ◽  
Thomas Kehagias ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Stacking Faults ◽  
High Resolution Electron Microscopy ◽  
High Energy ◽  
Low Energy ◽  
Inversion Domain ◽  
Resolution Electron ◽  
Domain Boundaries ◽  
Inversion Domain Boundaries

ABSTRACTThe interaction of growth intrinsic stacking faults with inversion domain boundaries in GaN epitaxial layers is studied by high resolution electron microscopy. It is observed that stacking faults may mediate a structural transformation of inversion domain boundaries, from the low energy types, known as IDB boundaries, to the high energy ones, known as Holt-type boundaries. Such interactions may be attributed to the different growth rates of adjacent domains of inverse polarity.

Junction lines of inversion domain boundaries with stacking faults in GaN

2004 ◽  
Vol 70 (11) ◽  
Author(s):  
J. Kioseoglou ◽  
G. P. Dimitrakopulos ◽  
Ph. Komninou ◽  
H. M. Polatoglou ◽  
A. Serra ◽  
...  
Keyword(s):  
Stacking Faults ◽  
Inversion Domain ◽  
Domain Boundaries ◽  
Inversion Domain Boundaries

Phase Stability of the Sigma Phase in Fe-Cr Based Alloys

1995 ◽  
Vol 408 ◽  
Author(s):  
Marcel Il. F ◽  
Sluiter. Koivan Esfurjani ◽  
Yoshiyuki Kawazoe
Keyword(s):  
Total Energy ◽  
Phase Stability ◽  
First Principles ◽  
Finite Temperature ◽  
Sigma Phase ◽  
Complex Structure ◽  
Unit Cell ◽  
Energy Calculations ◽  
Cluster Variation ◽  
The Stability

AbstractThe FeCr sigma phase is a good example of a complex structure: it. has 30 atoms in the unit cell and 5 inequivalent lattice sites, and it belongs to the class of tetrahedrally close packed structures, also known as Frank-Kaspar structures. So far. such structures have riot been treated within a first-principles statistical thermodynamics framework. It will be shown that dtlme to advances in algorithms and hardware important features of the phase stability of complex phases can be computed. The factors which affect the stability of the sigma phase have been studied using carefully selected supercells for electronic total energy calculations. cluster variation calc:ulations in the tet.rahedron approximation were performed to evaluate the effect of partial disorder and of finite temperature. The preferred occupancy of the 5 lattice sites has been investigated and is compared with experimental determinations.

Microstructral Investigations on GaN Films Grown by Laser Induced Molecular Beam Epitaxy

1999 ◽  
Vol 595 ◽  
Author(s):  
H. Zhou ◽  
F. Phillipp ◽  
M. Gross ◽  
H. Schröder
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Threading Dislocations ◽  
Planar Defects ◽  
Sapphire Substrates ◽  
Inversion Domain ◽  
Transmission Electron ◽  
Domain Boundaries ◽  
Line Defects ◽  
Inversion Domain Boundaries

AbstractMicrostructural investigations on GaN films grown on SiC and sapphire substrates by laser induced molecular beam epitaxy have been performed. Threading dislocations with Burgers vectors of 1/3<1120>, 1/3<1123> and [0001] are typical line defects, predominantly the first type of dislocations. Their densities are typically 1.5×1010 cm−2 and 4×109 cm−2 on SiC and sapphire, respectively. Additionally, planar defects characterized as inversion domain boundaries lying on {1100} planes have been observed in GaN/sapphire samples with an inversion domain density of 4×109 cm−2. The inversion domains are of Ga-polarity with respect to the N-polarity of the adjacent matrix. However, GaN layers grown on SiC show Ga-polarity. Possible reasons for the different morphologies and structures of the films grown on different substrates are discussed. Based on an analysis of displacement fringes of inversion domains, an atomic model of the IDB-II with Ga-N bonds across the boundary was deduced. High resolution transmission electron microscopy (HRTEM) observations and the corresponding simulations confirmed the IDB-II structure determined by the analysis of displacement fringes.

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