scholarly journals First-principles accurate total energy surfaces for polar structural distortions ofBaTiO3,PbTiO3, andSrTiO3: Consequences for structural transition temperatures

2010 ◽  
Vol 82 (13) ◽  
Author(s):  
Takeshi Nishimatsu ◽  
Masaya Iwamoto ◽  
Yoshiyuki Kawazoe ◽  
Umesh V. Waghmare
Keyword(s):  
Total Energy ◽  
First Principles ◽  
Structural Transition ◽  
Transition Temperatures ◽  
Structural Distortions ◽  
Energy Surfaces

scholarly journals Theory of Hydrogen Reactions in Silicon

1987 ◽  
Vol 104 ◽  
Author(s):  
Chris G. Van De Walle ◽  
Y. Bar-Yam ◽  
S. T. Pantelides
Keyword(s):  
Fermi Level ◽  
Total Energy ◽  
First Principles ◽  
Type Material ◽  
Energy Calculations ◽  
And Migration ◽  
The Stability ◽  
Hydrogen Reactions ◽  
Energy Surfaces ◽  
P Type

ABSTRACTWe report first-principles total-energy calculations for H atoms in a Si lattice. Our results for single H atoms are presented in the form of total-energy surfaces, providing immediate insight in stable positions and migration paths. We examine the stability of different charge states (H+, H0, H−) as a function of Fermi-level position, and its impli-cations for H diffusion in p-type vs. n-type material. The results are used to scrutinize and supplement existing understanding of experimental observations. We also study the co-operative interactions of several H atoms, and propose a novel mechanism for H-induced damage.

To Bend or Not to Bend, the Dilemma of Multiple Bonds

2019 ◽  
Author(s):  
Michele Pizzocchero ◽  
Matteo Bonfanti ◽  
Rocco Martinazzo
Keyword(s):  
First Principles ◽  
2D Materials ◽  
Main Group ◽  
First Principles Calculations ◽  
Group 14 ◽  
Multiple Bonds ◽  
Main Group Elements ◽  
Structural Distortions

The manuscript addresses the issue of the structural distortions occurring at multiple bonds between high main group elements, focusing on group 14. These distortions are known as trans-bending in silenes, disilenes and higher group analogues, and buckling in 2D materials likes silicene and germanene. A simple but correlated \sigma + \pi model is developed and validated with first-principles calculations, and used to explain the different behaviour of second- and higher- row elements.

Site preference and atomic ordering in the ternary Rh5Ga2As: first-principles calculations

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Nilanjan Roy ◽  
Sucharita Giri ◽  
Harshit ◽  
Partha P. Jana
Keyword(s):  
Total Energy ◽  
First Principles ◽  
Density Functional ◽  
Structure Type ◽  
Site Preference ◽  
X Ray Diffraction ◽  
Atomic Ordering ◽  
Functional Theory ◽  
The Stability ◽  
Bonding Characteristics

Abstract The site preference and atomic ordering of the ternary Rh5Ga2As have been investigated using first-principles density functional theory (DFT). An interesting atomic ordering of two neighboring elements Ga and As reported in the structure of Rh5Ga2As by X-ray diffraction data only is confirmed by first-principles total-energy calculations. The previously reported experimental model with Ga/As ordering is indeed the most stable in the structure of Rh5Ga2As. The calculation detected that there is an obvious trend concerning the influence of the heteroatomic Rh–Ga/As contacts on the calculated total energy. Interestingly, the orderly distribution of As and Ga that is found in the binary GaAs (Zinc-blende structure type), retained to ternary Rh5Ga2As. The density of states (DOS) and Crystal Orbital Hamiltonian Population (COHP) are calculated to enlighten the stability and bonding characteristics in the structure of Rh5Ga2As. The bonding analysis also confirms that Rh–Ga/As short contacts are the major driving force towards the overall stability of the compound.

Total energy surfaces in the M-V plane for bcc and fcc cobalt

1986 ◽  
Vol 54-57 ◽  
pp. 955-956 ◽  
Author(s):  
V.L. Moruzzi ◽  
P.M. Marcus ◽  
K. Schwarz ◽  
P. Mohn
Keyword(s):  
Total Energy ◽  
Energy Surfaces

First-Principles Total Energy Study of NbCr2 + V Laves Phase Ternary System

1998 ◽  
Vol 552 ◽  
Author(s):  
Alim Ormeci ◽  
S. P. Chen ◽  
John M. Wills ◽  
R. C. Albers
Keyword(s):  
Ternary System ◽  
Total Energy ◽  
Density Of States ◽  
First Principles ◽  
Laves Phase ◽  
Full Potential ◽  
Self Consistent ◽  
Substitutional Defects ◽  
Cohesive Energies ◽  
Formation Energies

ABSTRACTThe C15 NbCr2 + V Laves phase ternary system is studied by using a first-principles, self-consistent, full-potential total energy method. Equilibrium lattice parameters, cohesive energies, density of states and formation energies of substitutional defects are calculated. Results of all these calculations show that in the C15 NbCr2 + V compounds, V atoms substitute Cr atoms only.

STRUCTURAL TRANSITIONS OF BiI3 UNDER PRESSURE

2012 ◽  
Vol 26 (32) ◽  
pp. 1250217
Author(s):  
XIAO-XIAO SUN ◽  
ZHI-RU REN ◽  
DAO-GUANG WANG
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Structural Transition ◽  
High Pressures ◽  
Functional Theory ◽  
High Pressure Studies ◽  
Volume Collapse ◽  
Pseudopotential Calculations ◽  
Structural And Electronic Properties ◽  
Pnma Phase

High pressure studies of BiI 3 at 0 K are performed using first-principles pseudopotential calculations within the framework of density functional theory. The calculations indicate that BiI 3 undergoes a structural transition from rhombohedral R-3 phase to monoclinic P2 1/c phase at 7 GPa which is accompanied by a 5.8% volume collapse. In addition, we find that P2 1/c phase prevails about 60 GPa range and transforms to cubic Fm-3m phase at 68 GPa, and finally takes the orthorhombic Pnma phase at high pressures up to 133 GPa. The structural and electronic properties of four competitive structures are also calculated. The analysis of density of states reveals that BiI 3 has semiconductor-metal transition at about 61 GPa, which also demonstrates the metallic nature of both Fm-3m and Pnma phases.

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