Multiscale Computational Model of Nitride Semiconductor Nanostructures

2012 ◽  
Vol 560-561 ◽  
pp. 1133-1137
Author(s):  
Karine Abgaryan ◽  
Ilya Mutigullin ◽  
Dmitriy Bazhanov

Theoretical multiscale model of nitride semiconductor nanostructure is proposed. The model combines various computational methods such as density functional theory, molecular dynamics and kinetic Monte Carlo. As a first step of implementation of proposed approach ab initio calculations of structural and electronic properties of two different structures InN/Si and AlN/AlGaN/GaN heterostructures were carried out. In particular, the influence of oxygen on InN/Si adhesion energy was studied. AlN, GaN, AlxGa1-xN (x=0.33) spontaneous and piezoelectric polarizations as well as sheet carrier concentrations at GaN/AlGaN interface were calculated. Obtained value for sheet carrier concentration at GaN/AlGaN interface is close to experimental data.

Author(s):  
K. L. Galav ◽  
K. B. Joshi

In this paper, structural and electronic properties of L12 and D019- AlSc 3 are presented. Calculations are performed applying crystalline orbital program within the framework of density functional theory. The exchange and correlation are treated following the Perdew–Becke–Ernzerhof ansatz. Other Al – Sc intermetallic compounds and polymorphs of Al 3 Sc , Al 2 Sc and AlSc are also investigated. The total energy calculations are coupled with the Murnaghan equation of state to determine lattice constants and bulk moduli. The data for D019- AlSc 3 are provided while deduced structural parameters for other materials are compared with the available results. Current results are reasonably in agreement with the experimental data and other reported calculations. Electronic band structures of a few Al – Sc compounds are studied with a view to examine effect of Al concentration on the formation of bands and bonds in the Al – Sc system.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mohammad Qasemnazhand ◽  
Farhad Khoeini ◽  
Farah Marsusi

AbstractIn this study, based on density functional theory, we propose a new branch of pseudo-fullerenes which contain triple bonds with sp hybridization. We call these new nanostructures fullerynes, according to IUPAC. We present four samples with the chemical formula of C4nHn, and the structures derived from fulleranes. We compare the structural and electronic properties of these structures with those of two common fullerenes and fulleranes systems. The calculated electron affinities of the sampled fullerynes are negative, and much smaller than those of fullerenes, so they should be chemically more stable than fullerenes. Although fulleranes also exhibit higher chemical stability than fullerynes, but pentagon or hexagon of the fullerane structures cannot pass ions and molecules. Applications of fullerynes can be included in the storage of ions and gases at the nanoscale. On the other hand, they can also be used as cathode/anode electrodes in lithium-ion batteries.


2006 ◽  
Vol 62 (6) ◽  
pp. 1025-1030 ◽  
Author(s):  
Razvan Caracas ◽  
Renata M. Wentzcovitch

Density functional theory is used to determine the possible crystal structure of the CaSiO3 perovskites and their evolution under pressure. The ideal cubic perovskite is considered as a starting point for studying several possible lower-symmetry distorted structures. The theoretical lattice parameters and the atomic coordinates for all the structures are determined, and the results are discussed with respect to experimental data.


2013 ◽  
Vol 321-324 ◽  
pp. 495-498 ◽  
Author(s):  
Dong Chen ◽  
Chao Xu

The reflectivity, loss function, refractive index, extinction coefficient and dielectric function of the LaNi5and LaNi4.5Sn0.5intermetallic compounds are investigated through the plane-wave pseudo-potential method based on the density functional theory. The effects of Sn impurity are discussed and some interesting features are found in the low frequency region. Some important optical properties such as static dielectric constant and static refractive index are obtained. The equation [n (0)]2=ε1(0)is satisfied according to our calculation, which indicates that our results are correct and reasonable. Nevertheless, the calculated results need to be testified in the future due to the lack of experimental data.


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