Electronic Structure and Bonding at the Al-terminated Al(111)/α-Al2O3(0001) Interface: A First Principles Study

2000 ◽  
Vol 654 ◽  
Author(s):  
Donald J. Siegel ◽  
Louis G. Hector ◽  
James B. Adams
Keyword(s):  
First Principles ◽  
Bond Order ◽  
Minimum Energy ◽  
Covalent Character ◽  
Population Analyses ◽  
Bonding Interaction ◽  
Optimized Model ◽  
Α Al2o3 ◽  
Mayer Bond Order ◽  
Atomic Coordinates

AbstractWe have performed ab initio calculations to determine the bonding character of the Al-terminated Al(111)/α-Al2O3(0001) interface. By using an optimized model in which all atomic coordinates were relaxed to their minimum energy positions, we have determined that Al-O bonds constitute the primary interfacial bonding interaction. Our electron localization, Mayer bond order, and Mul- liken population analyses reveal that these bonds are very similar to the cation-anion bonds found in the bulk oxide, and are therefore mainly ionic, with a smaller amount of covalent character. However, there is also evidence of metal-cation bonding across the interface, a result which could be significant to understanding bonding at interfaces with other corundum-like oxides.

SCF-MO computational analysis of the geometric conformation and charge distribution in picric acid and alkali picrate salts

1996 ◽  
Vol 74 (1) ◽  
pp. 70-78 ◽  
Author(s):  
Zbigniew Zimpel ◽  
Barbara R. Nelson ◽  
John A. Weil
Keyword(s):  
Charge Distribution ◽  
Computational Analysis ◽  
Picric Acid ◽  
Minimum Energy ◽  
Mulliken Charge ◽  
Resonance Effects ◽  
Molecular Electron ◽  
Optimized Model ◽  
Atomic Coordinates ◽  
Density Results

SCF-MO computations were employed in a study of picric acid, the –1 picrate ion, and Li, Na, and K picrates. Atomic coordinates from crystallographic structural analyses were used as initial parameters in the computation of the minimum-energy conformations of each free molecule at the 6-31G level. The Mulliken charge numbers for each atom in the optimized model molecules were calculated at the 6-31G** level. The induction and resonance effects of the OX group (X = H, Li, Na, K) on the trinitrophenyl ring are discussed. It is demonstrated that molecular (electron) isodensity surfaces (MIDCOs) describe charge-density results nicely compatible with the point Mulliken charge numbers. Key words: picrates, SCF-MO, charge distribution.

First-principles calculations of group IIA and group IV impurities in α−Al2O3

2020 ◽  
Vol 4 (7) ◽  
Author(s):  
Toshihiro Futazuka ◽  
Ryo Ishikawa ◽  
Naoya Shibata ◽  
Yuichi Ikuhara
Keyword(s):  
First Principles ◽  
Group Iv ◽  
First Principles Calculations ◽  
Α Al2o3

Helium stability and its interaction with H in α-Al2O3: a first-principles study

2016 ◽  
Vol 18 (3) ◽  
pp. 1649-1656 ◽  
Author(s):  
Guikai Zhang ◽  
Xin Xiang ◽  
Feilong Yang ◽  
Xuexing Peng ◽  
Tao Tang ◽  
...  
Keyword(s):  
First Principles ◽  
First Principles Study ◽  
Α Al2o3

Forms of H and He-related defects in α-Al2O3are Hei, Hi+, [Hei–H+]+, [HeAl3−–H+]2−and [HO+–Hei]+.

Fast hydrogen diffusion along the Σ7 grain boundary of α-Al2O3: A first-principles study

2016 ◽  
Vol 41 (47) ◽  
pp. 22214-22220 ◽  
Author(s):  
Fei Wang ◽  
Wensheng Lai ◽  
Rusong Li ◽  
Bin He ◽  
Sufen Li
Keyword(s):  
Grain Boundary ◽  
First Principles ◽  
Hydrogen Diffusion ◽  
First Principles Study ◽  
Α Al2o3

First principles simulations of Cu and Au deposition on α-Al2O3 (0001) surface

2004 ◽  
Vol 238 (1-4) ◽  
pp. 228-232 ◽  
Author(s):  
Norge Cruz Hernández ◽  
Javier Fdez. Sanz
Keyword(s):  
First Principles ◽  
Α Al2o3

Ab-Initio Calculation of the β-SiC/Ni Interface

2001 ◽  
Vol 680 ◽  
Author(s):  
A. Blasetti ◽  
G. Profeta ◽  
S. Picozzi ◽  
A. Continenza ◽  
A. J. Freeman
Keyword(s):  
First Principles ◽  
Ab Initio Calculation ◽  
Surface States ◽  
Binding Energies ◽  
Bonding Mechanism ◽  
Covalent Character ◽  
Adsorption Sites ◽  
Barrier Heights ◽  
Adsorption Energies ◽  
The Stability

ABSTRACTWe investigate the adsorption of a Ni monolayer on the β-SiC(001) surface by means of highly precise first-principles all-electron FLAPW calculations. Total energy calculations for the Si- and C-terminated surfaces reveal high Ni adsorption energies, with respect to other metals, confirming the strong reactivity and the stability of the transition metal/SiC interface. These high binding energies, about 7.3-7.4 eV, are shown to be related to strong p-d hybridization, common to both surface terminations and different adsorption sites, which, despite the large mismatch, may stabilize overlayer growth. A detailed analysis of the bonding mechanism, in terms of density of states and hybridization of the surface states, reveals the strong covalent character of the bonding. We also calculate and discuss the Schottky barrier heights at the Ni/SiC junction for both terminations.

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