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Desenvolvimento de um algoritmo numérico na técnica do operador diferencial : aplicações em modelos de spins
(Universidade Federal de São Carlos, 2012-10-11)
In this work, we present the results obtained for Ising models and Heisenberg spin 1/2, where
two and three-dimensional, with disorder or frustration. We apply effective field theory
associated with the Operator Differential ...
Seções de choque da interação de elétrons de energias intermediárias com moléculas poliatômicas e constituintes do DNA
(Universidade Federal de São Carlos, 2012-09-14)
Elastic Differential Cross Sections (EDCS) were measured for the interaction of electrons in the incident energy range of 100-1000 eV, with several polyatomic molecules, namely: ethane (C2H6), propane (C3H8), methanol ...
Propriedades magnéticas de nanofios de cobalto autoformados por deposição à laser pulsado
(Universidade Federal de São Carlos, 2012-02-15)
Le sujet de cette thèse est l étude de nanofils de cobalt dans une matrice d oxyde de cérium (CeO2) épitaxiée sur SrTiO3(001). L auto-assemblage de nanofils a été mis en évidence lors de la croissance de couches minces de ...
Estrutura de platô na magnetização em modelos de spins frustrados
(Universidade Federal de São Carlos, 2012-10-26)
This thesis study the phase transition, forms classical and quantum models of spin frustration. The Heisenberg model of spin 1/2 with exchange anisotropy with competitive interactions between first (J1) and second (J2) ...
Efeitos de spin em diodos de tunelamento ressonante tipo-p
(Universidade Federal de São Carlos, 2012-03-27)
In this work, we have investigated the spin effects in p-i-p GaAs/AlAs resonant tunneling diodes under magnetic field parallel to the tunnel current. The spin-dependent tunneling of carriers was studied by analyzing the ...
Simulações de líquidos super-resfriados via dinâmica molecular
(Universidade Federal de São Carlos, 2012-10-15)
This work presents the study of two models of glass-forming liquids using molecular dynamics simulations. The first model aims to analyze the effects on glassy dynamics which allow the enhancement of the glass formability ...
Estudo de primeiros princípios das propriedades eletrônicas de novos materiais derivados do grafeno : as nanofitas e nanofios
(Universidade Federal de São Carlos, 2012-09-05)
In this thesis, we study new materials derived from graphene, like nanowires and nanoribbons, with numerical calculations based on the density functional theory (DFT) and the non-equilibrium Green functions (NEGF). We will ...
Efeitos eletrônicos, elásticos e estruturais em sistemas semicondutores nanoscópicos
(Universidade Federal de São Carlos, 2012-02-16)
The present work aims the study of electronic, elastic and structural properties of a whole class of nanoscopic semiconductors systems, which include quasi-two-dimensional, one-dimensional and zero-dimensional confined ...