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Estrutura eletrônica de anéis quânticos
(Universidade Federal de São Carlos, 2011-08-09) Oliveira Neto, Vivaldo Lopes; Richard, Victor Lopez; https://lattes.cnpq.br/0638704940221279; https://lattes.cnpq.br/6937374774888445
The nanoscopic structures with ring topology, or quantum rings, have attracted the interest due to their unique rotational symmetry and the possibility of checking fundamental quantum phenomena. Among them, the study of Aharonov-Bohm interference effects appears with special emphasis. Analytical calculations of the electronic structure of quantum rings were performed for the electron confined in one-dimensional and threedimensional potentials. These calculations were complemented by the electronic structure simulation of the valence band using the k.p method, main objective this work. This theoretical contribution is a part of a collaboration with experimental groups of growth and spectroscopy which deal with problems related to the manipulation of electronic states and spin properties of quantum rings. The ground states of both electrons and holes in quantum dots (quasi-zero-dimensional systems) have zero angular momentum (in the absence of magnetic fields and low fields) and exhibit a diamagnetic response of the spin states in the presence of an external magnetic field. In non-magnetic quantum dots, the spin properties are mainly attributed to the electron spin and the heavy hole. On the other hand, it is assumed that the light holes have a minor role in the properties of the exciton ground state. Our results show that the interband coupling may lead to the angular momentum hybridization of the electronic states, even in the ground state and the the light hole may assume a relevant role. The adaptation and improvement of calculations of the electronic structure using the k.p methods were two of the main objectives of this work. The theoretical tools developed aim to contribute to the establishment of protocols for optimal use and application of such systems.
Segregação socioespacial: os condomínios horizontais na cidade de São Carlos/SP
(Universidade Federal de São Carlos, 2011-08-09) Nardin, Juliana de; Francisco, José; https://lattes.cnpq.br/0330065027402518; https://lattes.cnpq.br/8649723884955257
This dissertation focuses the closed horizontal condominiums and subdivisions in the city of São Carlos that appeared in the 1970s consolidating itself as the form of housing of highincome classes that seek parts far from the center to live within the walls. In 1976 in São Carlos, it was deployed Parque Sabará the first enterprise of this tipe since then, the condominiums expanded and hold large areas of the city. They are located as in portions more remote as in the consolidated urban area. This dynamic is increasing in many Brazilian cities, as evidenced by the growing production of work aimed at this issue. This way, there are discussions and questions the social perspective, as an ingredient of socio-spatial segregation, or in relation to the legality of the establishment of these enterprises, that do not have specific legislation that regulates us. Therefore, the dissertation refers to the study and analysis of closed residential subdivisions and condominiums in São Carlos, and the transformations inserted in the context of the deployment of these enterprises. The research is based in literature search, documentary, photographic and visits to investigate the production of urban space from the closed condominiums and subdivisions set in a dynamic real estate production. This study was guided by the discussion of socio-spatial segregation and the capitalist production of space that impose occupation patterns that spread and are responsible for maintaining the capital.