Density functional tight binding study of β-Ga2O3: Electronic structure, surface energy, and native point defects

2019 ◽  
Vol 150 (17) ◽  
pp. 174706 ◽  
Author(s):  
Jonghoon Lee ◽  
Sabyasachi Ganguli ◽  
Ajit K. Roy ◽  
Stefan C. Badescu
Keyword(s):  
Electronic Structure ◽  
Surface Energy ◽  
Point Defects ◽  
Density Functional ◽  
Tight Binding ◽  
Binding Study ◽  
Native Point Defects ◽  
Structure Surface

scholarly journals Simulations of Defect-Interface Interactions in GaN

2000 ◽  
Vol 5 (S1) ◽  
pp. 287-293
Author(s):  
J. A. Chisholm ◽  
P. D. Bristowe
Keyword(s):  
Electronic Structure ◽  
Binding Energy ◽  
Point Defects ◽  
Potential Model ◽  
Pair Potential ◽  
Planar Defects ◽  
Native Defects ◽  
Native Point Defects ◽  
Bulk Gan ◽  
Image Position

We report on the interaction of native point defects with commonly observed planar defects in GaN. Using a pair potential model we find a positive binding energy for all native defects to the three boundary structures investigated indicating a preference for native defects to form in these interfaces. The binding energy is highest for the Ga interstitial and lowest for vacancies. Interstitials, which are not thought to occur in significant concentrations in bulk GaN, should form in the (11 0) IDB and the (10 0) SMB and consequently alter the electronic structure of these boundaries.

First-principles insights into ammonia decomposition on MoN (0001) surface

2021 ◽  
Author(s):  
kun yuan ◽  
pengju hao ◽  
Xiaolin Li ◽  
Yang Zhou ◽  
jiangbo zhang ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Surface Energy ◽  
Geometric Structure ◽  
First Principles ◽  
Density Functional ◽  
Slab Model ◽  
Ammonia Adsorption ◽  
Functional Theory ◽  
Dehydrogenation Mechanism

Density functional theory (DFT) and periodic slab model were used to study the geometric structure, electronic structure and dehydrogenation mechanism of ammonia adsorption on MoN (0001) surface. The surface energy...

scholarly journals Thermal bridging of graphene nanosheets via covalent molecular junctions: A non-equilibrium Green’s functions–density functional tight-binding study

Nano Research ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 791-799 ◽  
Author(s):  
Diego Martinez Gutierrez ◽  
Alessandro Di Pierro ◽  
Alessandro Pecchia ◽  
Leonardo Medrano Sandonas ◽  
Rafael Gutierrez ◽  
...  
Keyword(s):  
Density Functional ◽  
Green's Functions ◽  
Green’S Functions ◽  
Graphene Nanosheets ◽  
Tight Binding ◽  
Molecular Junctions ◽  
Binding Study ◽  
Thermal Bridging ◽  
Non Equilibrium

Computational studies of energetics, electronic structure, and vibrational spectra of PETN nanoparticles

2021 ◽  
Vol 99 (1) ◽  
pp. 63-71
Author(s):  
Qiannan Ma ◽  
Weihua Zhu
Keyword(s):  
Electronic Structure ◽  
Vibrational Spectra ◽  
Density Functional ◽  
Solid Phase ◽  
Tight Binding ◽  
High Energy ◽  
Pentaerythritol Tetranitrate ◽  
Energy Bands ◽  
Extra Energy ◽  
The Stability

The density functional tight binding method was used to explore the energetics, electronic structure, and vibrational spectra of pentaerythritol tetranitrate (PETN) nanoparticles (NPs). The surface energy of the PETN NP is anisotropic and its extra energy decreases with the increase of size. The energy bands of the NPs are significantly expanded and the band gaps are narrowed, thus reducing the stability due to nanometer size effect. The surface of the NP is mainly covered by the NO2 group. The high-energy surface may play a role in triggering chemical decomposition. The vibration frequencies of the PETN NPs present a wider distribution than those of the gas and solid phase PETN, which will increase the probability of energy transfer to the molecules in the system and promote the decomposition of PETN. Our results provide a basic understanding from a molecular perspective to the energy properties of nano explosives.

Combined tight-binding/DFT investigation of the electronic structure of triimine-platinum(II)/TCNQ extended stacks,

2009 ◽  
Vol 87 (7) ◽  
pp. 775-783 ◽  
Author(s):  
Hassan Rabaâ ◽  
Thomas R. Cundari ◽  
Mohammad A. Omary
Keyword(s):  
Electronic Structure ◽  
Density Functional ◽  
Tight Binding ◽  
Negative Energy ◽  
Large Contribution ◽  
Redox Potentials ◽  
Absorption Bands ◽  
Metallic Behavior ◽  
Charge Delocalization ◽  
Donor Acceptor

. The [Pt(tbtrpy)(X)][TCNQ] (X = OH or SH) complexes form sandwich stacks with nitrile acceptors leading to extended-chain supramolecular assemblies, tbtrpy = 4,4′,4″-tert-Bu3-2,2′:6′,2″-terpyridine. Calculations with the extended Hückel tight-binding (EHTB) method are performed upon crystalline {[Pt (tbtrpy)(X)][TCNQ]}∞ species to analyze their electronic structure and consequent properties, TCNQ = 7,7,8,8-tetracyanoquinodimethane. The donor/acceptor extended chains in the solid state are predicted to exhibit metallic behavior with a large contribution from π and π* bands of TCNQ to the valence and conduction bands, respectively. Moreover, the valence band moves upward (i.e., to a less negative energy) for X = SH as compared to X = OH. Density functional theory (DFT) calculations suggest that this is due to large thiolate character in the HOMO of the square-planar donor complex, which also supports the experimental assignment of the electronic absorption bands and redox potentials. Calculations of infrared (νCN bands of TCNQ) and structural (CC bond lengths within TCNQ) data explain the metallic behavior of the stacks in terms of charge delocalization, leading to fractionally-charged species of the form [Pt(tbtrpy)X](1+δ)+[TCNQ](1+δ)- with δ > 0 and a greater δ value for X = SH vs OH.

Native point defects in multicomponent transparent conducting oxides

2014 ◽  
Vol 1633 ◽  
pp. 37-42
Author(s):  
Altynbek Murat ◽  
Julia E. Medvedeva
Keyword(s):  
Oxygen Vacancy ◽  
Point Defects ◽  
Density Functional ◽  
Defect Formation ◽  
Conducting Oxides ◽  
Cation Vacancies ◽  
Native Point Defects ◽  
Wide Range ◽  
Growing Conditions ◽  
Donor Defect

ABSTRACTThe formation of native point defects in layered multicomponent InAMO4 oxides with A3+=Al or Ga, and M2+=Ca, Mg, or Zn, is investigated using first-principles density functional calculations. We calculated the formation energy of acceptor (cation vacancies, acceptor antisites) and donor (oxygen vacancy, donor antisites) defects within the structurally and chemically distinct layers of InAMO4 oxides. We find that the antisite donor defect, in particular, the A atom substituted on the M atom site (AM) in InAMO4 oxides, have lower formation energies, hence, higher concentrations, as compared to those of the oxygen vacancy which is know to be the major donor defect in binary constituent oxides. The major acceptor (electron “killer”) defects are cation vacancies except for InAlCaO4 where the antisite CaAl is the most abundant acceptor defect. The results of the defect formation analysis help explain the changes in the observed carrier concentrations as a function of chemical composition in InAMO4, and also why the InAlZnO4 samples are unstable under a wide range of growing conditions.

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