A influência da interação elétron-elétron na localização de Anderson e na localização dinâmica em sistemas de baixa densidade eletrônica

• Ano de defesa: 2020
• Autor(a) principal: Coêlho, Michele Bertoldo
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Alagoas; Brasil; Programa de Pós-Graduação em Física; UFAL
• Palavras-chave em Português: Transporte eletrônico; Interação elétron-elétron; Modelo de Anderson; Oscilações de Bloch; Transport properties; Electron-electron interaction; Disroder; Bloch oscillations; CNPQ::CIENCIAS EXATAS E DA TERRA::FISICA
• Link de acesso: http://www.repositorio.ufal.br/handle/riufal/7464

Electronic transport properties in systems of interacting electrons are a central topic within solid state physics. However, besides the high computational cost, these systems can feature restrictions to consider perturbative methods. In this scenario, low electronic density models have been proven as a good alternative to the study, being able to rescue important aspects which are present in many interacting particle systems. One of this phenomenon is the weakening of Anderson localization promoted by electron-electron interaction. Such phenomenology was reported initially in experimental studies of persistent currents in mesoscopic rings. However, similar behavior is present in fermions in optical grids, ultracould condensates, Anderson-Hubbard in 1D, 2D and 3D and 2D Coulomb glasses, suggesting some degree of competition between disorder and interaction. Among these works on this topic, we highlight the paper of Dias and Lyra[Physica A 411 (2014) 35–41], who studied two electrons moving in a random one-dimensional potential landscape, where has been demonstrated a nonmonotonic influence of the electron-electron interaction on the Anderson localization. Another interesting phenomenon arises from the low-density proposal is the Bloch frequency doubling caused by the interaction between electrons in 1D systems, going against results of many-body which showed that the interaction acts destructively on the Bloch oscillations. The result of the Bloch frequency doubling was theoretically foreseen by Dias and coauthors[Phys. Rev. B 76 (2007) 155124] and experimentally proven later[Science 347 (2015) 1229–1233]. In the present thesis we present studies involving both scenarios. At a first moment we investigated the existence of non monotonic behavior of Anderson localization in one-dimensional chain with structural disorder[Physica E 124 (2020) 114371]. Later, we presented our studies considering the Bloch oscillations for a system of interacting electrons, assuming now the inclusion of a non-local interaction between particles term. Both systems studied reveal the relevant role which inclusion of interaction between particles therm can effect on the electrons dynamics. The results reveal competitive aspects between different electronic states present in the system.