Self Consistent Calculations
Mostrando 1-12 de 30 artigos, teses e dissertações.
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1. Estudo da desativação do agente VX usando o MgO por cálculos ab initio
The organophosphates are used in industry, in the fields of dyes, varnishes, artificial leather, electrical insulation, waterproofing, plastics, oil additives and solvents, are also used in medicine to treat diseases such as glaucoma, in the household and in agriculture are applied as insecticides and pesticides. Besides these various civilian facilities, th
Publicado em: 2009
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2. Estudo de poços parabólicos largos de AIGaAs em campos magnéticos altos / Study of wide parabolic quantum wells of AlGaAs in high magnetic fiels
We present the results of experiments and calculations done on AlGaAs Parabolic Quantum Wells (PQWs) grown on GaAs by molecular beam epitaxial tecniques. Transport measurements in n-type and p-type samples with widths between 1000 ºA and 4000 ºA at low temperatures indicate an abrupt increase of the Hall coeficient at a critical field B ¼ 3 T. Our study f
Publicado em: 2007
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3. Theoretical innovation and computational experiments in Quantum Monte Carlo / Inovações teoricas e experimentos computacionais em Monte Carlo Quantico
The Hartree-Fock method (HF) is the principal strategy used in theoretical chemistry for electronic structure calculations. Although valuable results can be obtain with HF, this method has deficiencies in the treatment of some systems, which are related mainly with electronic correlation. Several methods were developed, known as "post-Hartree-Fock", in arder
Publicado em: 2005
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4. Unified study of electrical resistivity of simple and non-simple liquid metals
A model potential depending on an effective core radius but otherwise parameter free is used for the comparative study of electrical resistivity of simple and non-simple liquid metals. In the present paper electrical resistivity of simple and non-simple liquid metals have been calculated using Ziman's formula, Ziman's formula modified and used by Khajil and
Brazilian Journal of Physics. Publicado em: 2004-09
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5. Initial growth of GaN and InN over GaAs (110) substrates
We present, a systematic theoretical study of the adsorption of Ga, In and N over GaAs (110) surfaces based on parameter-free, self-consistent total energy and force calculations using the density functional theory. We analyzed the changes in the bond-lengths and in the bond-angles before and after deposition, as well as the total energy behaviour with the a
Brazilian Journal of Physics. Publicado em: 2004-06
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6. Carbon based nanostructures: diamond clusters structured with nanotubes
Feasibility of designing composites from carbon nanotubes and nanodiamond clusters is discussed based on atomistic simulations. Depending on nanotube size and morphology, some types of open nanotubes can be chemically connected with different facets of diamond clusters. The geometrical relation between different types of nanotubes and different diamond facet
Materials Research. Publicado em: 2003-01
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7. Subband structure of II-VI modulation-doped magnetic quantum wells
Here we investigate the spin-dependent subband structure of newly-developed Mn-based modulation-doped quantum wells. In the presence of an external magnetic field, the s-d exchange coupling between carriers and localized d electrons of the Mn impurities gives rise to large spin splittings resulting in a magnetic-field dependent subband structure. Within the
Brazilian Journal of Physics. Publicado em: 2002-06
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8. Low temperature static behavior of the two-dimensional quantum easy-axis Heisenberg model
We use the self-consistent harmonic approximation (SCHA) to study static properties of the two-dimensional quantum Heisenberg model with easy-axis anisotropy. We calculate the critical temperature as a function of the spin value, and compare with classical results. Specifically, we compare how the ratio of critical temperatures varies as a function of the sp
Brazilian Journal of Physics. Publicado em: 2000-06
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9. Propriedades Óticas de Estruturas Semicondutoras com Dopagem Planar do Tipo n ou p / Optical properties of semiconductor structures with doping Flat Type n or p
Estruturas semicondutoras com dopagem planar são sistemas de considerável interesse tanto para a a pesquisa básica como para a aplicação em dispositivos. Neste trabalho caracterizamos estruturas semicondutoras com dopagem planar tipo n ou p, utilizando técnicas de espectroscopia ótica tais como fotoluminescencência (PL) e fotoluminescência-excitaç�
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 29/04/1998
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10. Tecnicas de renormalização aplicadas ao estudo da densidade de estados de sistemas desordenados
A general scheme for real space renormalization of formal scattering theory is presented and applied to the calculation of density of states (DOS) in some finite width systems. This technique is extended in a self-consistent way, to the treatment of disordered and partially ordered chains. Numerical results of moments and DOS are presented in comparison with
Publicado em: 1985
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11. Modelo teorico de laser DH de GaAs incluindo calculo auto-consistente de perfil de temperatura
In this work the temperature, carrier density, current density and gain profiles along the active region of a double-heterostructure GaAs - AlxGa1-xAs semiconductor laser have been investigated by a self-consistent iteractive rnethod developed in order to calculate these distributions. Current injection results in a temperature rise at the active region, whi
Publicado em: 1980
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12. Uma formulação autoconsistente não muffin-tin para o metodo APW, e sua aplicação ao GaAs
The APW method for calculating electronic energy bands in solids is based on the so called muffin-tin " (MT) approximation for the crystal potential. The potential is taken as spherically symmetric within spheres centered at the atomic sites, and constant outside the spheres. "Ad hoc" crystal potentials are obtained by superposing self-consistent atomic pote
Publicado em: 1979