Generalized Gradient Approximation
Mostrando 1-12 de 19 artigos, teses e dissertações.
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1. Estudio Ab-initio de propiedades estructurales, elásticas y electrónicas de nanohilos core/shell
ABSTRACT This Zinc oxide (ZnO) is widely used in different electronic devices due to its thermal, electronic, and piro-piezoelectric properties. Some of these properties are noticeable improvement at the nanoscale, specially when ZnO together with other material create heterostructures. Recently, core/shell nanowires have been synthesized in order to raise t
Matéria (Rio J.). Publicado em: 19/07/2018
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2. Improved Electronic Structure and Optical Performance of Bi2Te3-xSex From First-principle Calculations Within TB-mBJ Exchange Potential
Using the first-principle calculations of density functional theory within the (FP-LAPW) method, we have investigated the structural, electronic and optical properties of Bi2Te3-xSex alloys with compositions x = 0, 1, 2 and 3 of Se. The generalized gradient approximation functional of Wu and Cohen (GGA-PBE) is used to calculate ground state structural parame
Mat. Res.. Publicado em: 17/11/2017
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3. Ab. initio study of the structural, elastic, electronic and optical properties of Cu3N
Electronic, optical, elastic, properties of Copper nitride (Cu3N) in cubic anti- ReO3 phase have been studied using the full-potential augmented plane waves (FP-LAPW) within density functional theory (DFT) framework. Generalized gradient approximation (GGA), local density approximation (LDA), Perdew - Burke - Ernzerhof generalized parameterization of gradien
Mat. Res.. Publicado em: 01/04/2014
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4. Hetero-nanotubos sob pressão hidrostática: um estudo ab initio / Hetero-nanotubes under hydrostatic pressure: an ab initio study
In this work the electronic and structural properties of the hetero-nanotube bundles, composed of a CNT (6,0) encapsulated in a BNNT (14,0) (CNT (6,0)@BNNT (14,0)) and a BNNT (6,0) encapsulated in a CNT (14,0) (BNNT(6,0)@CNT (14,0)), under hydrostatic pressure. For this, we applied density functional theory and generalized gradient approximation to the excha
Publicado em: 2011
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5. Estudo de nanofios metálicos por primeiros principios
In the present work, we investigate electronic and structural properties of nanowires based on noble metals (Au,Ag,Pt,Pd) and mid-series 4d and 5d transition metals (W,Mo,Ta,Nb). We employ an ab initio methodology implemented in the SIESTA package, based in the Kohn-Sham formulation of density functional theory (DFT). The generalized gradient approximation (
Publicado em: 2010
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6. First principle calculation of potential and multi-channel transport in Fe/MgO/Fe hetero-junction
In this work we studied the behavior of multi-channel tunneling through a realistic Fe/MgO/Fe hetero-junction ab initio potential. For this purpose we obtained Fe/MgO/Fe(001) hetero-junction effective potentials using the full potential-linear augmented plane wave WIEN2k code together with the generalized gradient approximation for the exchange-correlation p
Brazilian Journal of Physics. Publicado em: 2009-04
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7. Estudo da adsorção de água em compostos tipo-brucita por cálculos ab initio
The anionic clays, also known as layered double hydroxides (LDH) or hydrotalcitelike compounds, constitute a family of materials whose chemical formula can be represented by: [M2+ (1x) Me3+ x(OH)2]x+ . Amx/ m .nH2O. These compounds have hydroxide planes, or layers, which become permanently positively charged by the substitution of divalent cations M2+ by tri
Publicado em: 2008
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8. Caracterização energética e estrutural da interação DNA-cisplatina pela teoria do funcional da densidade
Estudo do sistema DNA-cisplatina usando a teoria do funcional da densidade (DFT) compara a eficiência dos funcionais de correlação e troca LDA e GGA(PBE) na simulação das bases nitrogenadas como também os conjuntos de base DZP e DZ. Fazendo as opções DZP e LDA e com a utilização de pseudopotenciais Ceperley-Alder de norma conservada executa cálcul
Publicado em: 2007
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9. CaracterizaÃÃo energÃtica e estrutural da interaÃÃo DNA-cisplatina pela teoria do funcional da densidade
Study of the DNA-cisplatin system using the Density Functional Theory(DFT), compares the eficiency of the correlation and exchange functionals LDA and GGA (PBE) in the simulation of the nitrogen bases as well as the basis sets DZP and DZ. Taking DZP and LDA options and with the use of the norm-conserved pseudopotentials Ceperley-Alder, simulate the sistems;
Publicado em: 2007
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10. Study of First Principles of Bundles of Nanotubes of Boron Nitride, under Pressure Hydrostatic / Estudo de Primeiros Princípios de Bundles de Nanotubos de Nitreto de Boro sob Pressão Hidrostática
In this work were studied the electronic, vibrations and structural properties of boron nitride nanotube bundles (16,0), (12,0) and (8,0), when submitted to the hydrostatic pressure changes. To study such properties, we used the ab initio method employing density functional theory in the approach of the generalized gradient approximation. All the simulations
Publicado em: 2007
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11. CRISTAIS DE ÃCIDO GLUTÃMICO: CRESCIMENTO, CARACTERIZAÃÃO E CÃLCULOS AB INITIO / crystals of glutamic acid: growth, characterization and calculations ab initio.
O trabalho realizado nesta tese visa a cristalizaÃÃo do Ãcido glutÃmico, favorecendo a obtenÃÃo da fase α (metaestÃvel) em relaÃÃo ao polimorfo β. ApÃs a obtenÃÃo dos cristais realizaram-se as medidas experimentais de fluorescÃncia, com vistas a comparaÃÃo com os dados teÃricos obtidos, considerando as limitaÃÃes do mÃtodo de sim
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 19/09/2006
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12. Ab Initio study of half-metallic feature and electronic structure of A2FeMoO6 (A=Ba,Ca) magnetic system
We report several ab initio calculations performed over the A2FeMoO6 (A=Ba, Ca) double perovskite. Results show that it is an insulator for the spin up orientation and conductor for the other one. We investigate the electronic structure of A2FeMoO6 by means calculations of density of states for both spin orientations, based on the Density Functional Theory a
Brazilian Journal of Physics. Publicado em: 2006-09