Tunelamento anisotrópico em barreiras magnéticas em multicamadas de fósforo negro

• Autor(a) principal: Ramos, Matheus Pinheiro
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Ceará (UFC)
• Texto Completo: http://www.repositorio.ufc.br/handle/riufc/49126
• topic: Semicondutores anisotrópicos; Fosforeno; Barreiras magnéticas; Propriedades de transporte

Experimental achievement in 2004 of the first two-dimensional (2D) structure: Graphene, a monolayer of carbon atoms arranged in a honeycomb lattice, aroused enormous interest in the academic world in studying this and other possible 2D structures such as: silicon, boron nitride, germanene and a class of materials called transition metal dicalcogens such as niobium selenide (NbSe2) and molybdenum disulfide (MoS2), as they exhibit a wide range of behaviors, thus making them candidates for a large number of industrial applications. Among these structures, the black phosphorus, in which this study is based, has many interesting properties, such as anisotropy in its band structure and a direct energy gap that varies with the number of layers, which makes it promising not only in electronics but also in optoelectronics. The present work aims to study tunneling problems in magnetic barriers in black phosphor multilayers. First we will get, from the tight-binding model, the Hamiltonian that describes the behavior of the charge transporters. Then, within the two-band regime, we will approach the continuum, which in turn provides us with the effective mass model of that system. Working on the effective mass model, which despite being obtained from successive approximations is considered an excellent model for low energies of the dispersion ratio, we will calculate the Hamiltonian self-states with translation symmetry breaking along one of the directions, considering or not the presence of a uniform magnetic field in the system. Considering the wave functions in the regions with and without magnetic field, we will study the problem of tunneling in a magnetic barrier and extend our investigation to the case of a supernet of magnetic barriers through the technique called transfer matrix. We will examine the role of material anisotropy in transport properties, presenting the results of the transmission and reflection probabilities for different magnetic barrier orientations, for black phosphor multilayers, and for different directions of electron propagation in the structure.