Structure, Electronic Properties, and Defects of GaN Using a Self-Consistent Molecular-Dynamics Method

1996 ◽  
Vol 449 ◽  
Author(s):  
Petra Stumm ◽  
D. A. Drabold
Keyword(s):  
Molecular Dynamics ◽  
Electronic Properties ◽  
Density Functional ◽  
Local Density ◽  
Functional Theory ◽  
Electronic Signatures ◽  
Self Consistent ◽  
Dynamics Simulations ◽  
Dynamics Method ◽  
Good Agreement

ABSTRACTMolecular dynamics simulations are employed to study defects in GaN. We use local basis density functional theory within the local density approximation where charge transfer between the ions is included in an approximate fashion. We find good agreement for the band structure of wurtzite and zincblende GaN compared to other recent calculations, suggesting the suitability of our method to describe GaN. A 96 atom GaN supercell is used to study the relaxations and electronic properties of common defects in the crystal structure, including Ga and N vacancies and antisites. We analyze the electronic signatures of these defects.

Structure, Electronic Properties, Defects and Doping of AlN Using a Self-Consistent Molecular Dynamics Method

1997 ◽  
Vol 468 ◽  
Author(s):  
Petra Stumm ◽  
D. A. Drabold
Keyword(s):  
Molecular Dynamics ◽  
Electronic Properties ◽  
Density Functional ◽  
Local Density ◽  
Functional Theory ◽  
Electronic Signatures ◽  
Donor And Acceptor ◽  
Self Consistent ◽  
Dynamics Simulations ◽  
Cation Sites

ABSTRACTMolecular dynamics simulations are employed to study native defects and dopants in AlN. We use local basis density functional theory within the local density approximation where charge transfer between the ions is included in a self-consistent fashion. Employing this code we find reasonable agreement for the band structure compared to other recent calculations, suggesting the suitability of our method to adequately describe AlN.Wurtzite and zincblende 96 atom AlN cells are used to study the relaxations and electronic properties of common defects in the crystal structure, including vacancies and antisites. We investigate the electronic signatures of these defects. The local topology of column-IV impurities in anion and cation sites is studied. We analyze the lattice relaxations and electronic consequences of these impurities and identify midgap defect, donor and acceptor levels.

Elastic and electronic properties of cubic cerium oxide under pressure via first principles

2014 ◽  
Vol 28 (14) ◽  
pp. 1450070 ◽  
Author(s):  
Z. W. Niu ◽  
B. Zhu ◽  
Y. Cheng ◽  
R. N. Song ◽  
G. F. Ji
Keyword(s):  
Electronic Properties ◽  
Density Functional ◽  
Local Density ◽  
Lattice Parameters ◽  
Total Density ◽  
Functional Theory ◽  
Young’S Moduli ◽  
Shear Wave Velocities ◽  
Total Density Of States ◽  
Good Agreement

The elastic and electronic properties of cubic structure CeO 2 under pressure are investigated in the frame of density functional theory (DFT). By using the local-density approximation (LDA) plus U( LDA +U) method with U = 6 eV, the calculated lattice parameters, bulk modulus and elastic properties of the cubic CeO 2 at 0 GPa and 0 K are in good agreement with the available experimental data. The pressure dependences of lattice parameters, bulk and shear modulus, Debye temperature, Young's moduli, Poisson's ratio and the compressional and shear wave velocities of the cubic CeO 2 are obtained successfully. In addition, the total density of states (TDOS) and the band gaps of the cubic CeO 2 under pressures are also investigated. By comparing the results of LDA and LDA+U, both the conventional LDA and the LDA+U methods can be used to describe the structure of the cubic CeO 2 due to the electronic localization of 4f-electron in Ce which is not so strong. However, the LDA+U approach can obtain a proper shape of the density of electronic states that agrees well with the measured values.

Thermal Conductivity of Hexagonal SiC Nanowire by Nonequilibrium Molecular Dynamics Simulations

2014 ◽  
Vol 487 ◽  
pp. 102-105
Author(s):  
Zan Wang ◽  
Hua Wei Guan ◽  
Ke Dong Bi
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Free Path ◽  
Density Functional ◽  
Mean Free Path ◽  
Nonequilibrium Molecular Dynamics ◽  
Functional Theory ◽  
Sic Nanowires ◽  
Dynamics Simulations ◽  
Dynamics Method

Using nonequilibrium Molecular Dynamics method, thermal properties of hexagonal 4H-SiC and 6H-SiC nanowires are investigated. The quantum errors between realistic temperatures and Molecular dynamics temperatures are rectified based on Density Functional Theory. Thermal conductivities of 4H-SiC and 6H-SiC nanowires are both simulated from 50K to 800K. The scale effect on the thermal conductivity of nanowire is also investigated by varying the nanowires length from 10nm to 130nm. Results indicate, if the length of phonon mean free path is shorter than that of nanowire, phonon-surface scattering will surpass boundary scattering to contribute thermal resistances. Therefore, the thermal conductivity of 4H-SiC or 6H-SiC nanowire is mainly determined by the comparability between the length of nanowires and phonon mean free path.

ATOMIC GEOMETRY OF III-V SEMICONDUCTORS WITH Bi OVERLAYERS

1994 ◽  
Vol 01 (04) ◽  
pp. 495-499 ◽  
Author(s):  
A. UMERSKI ◽  
G.P. SRIVASTAVA
Keyword(s):  
Density Functional Theory ◽  
Tilt Angle ◽  
Density Functional ◽  
Local Density ◽  
Clean Surface ◽  
Functional Theory ◽  
X Ray ◽  
Self Consistent ◽  
Consistent Solution ◽  
Good Agreement

We use density functional theory (within the local density and pseudopotential approximations) to determine the equilibrium atomic positions of a number of III-V semiconductors with Bi overlayers. Our calculations are based on the complete self-consistent solution to the Kohn-Sham equations. The systems under consideration include GaAs(110), InP(110), and InAs(110) substrates, with zero, one, and two ordered monolayer coverages of Bi, within the Goddard (i.e., epitaxially continued) geometry. For the clean surfaces, our results compare well with existing LEED and X-ray standing wave analyses, as well as with recent Car-Parrinello type calculations. For the covered surfaces, we also obtain good agreement with any existing experimental observations. We find that the surface tilt angle of the clean surface systems is almost removed by the adsorption of a monolayer of Bi, and that the residual surface tilt angle can be related to the ionicity of the substrate.

Graphene adlayer growth between nonepitaxial graphene and Ni(111) substrate: a promising theoretical scheme

2020 ◽  
Author(s):  
Lijuan Meng ◽  
Jinlian Lu ◽  
Yujie Bai ◽  
Lili Liu ◽  
Tang Jingyi ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Density Functional Theory ◽  
Chemical Vapor Deposition ◽  
Molecular Dynamics Simulations ◽  
Vapor Deposition ◽  
Density Functional ◽  
Chemical Vapor ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Dynamics Simulations

Understanding the fundamentals of chemical vapor deposition bilayer graphene growth is crucial for its synthesis. By employing density functional theory calculations and classical molecular dynamics simulations, we have investigated the...

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