Propriedades físicas de um gás de elétrons 2D na presença de um campo magnético inclinado

• Ano de defesa: 2008
• Autor(a) principal: Alves, Tayroni Francisco de Alencar
• Orientador(a): Costa Filho, Raimundo Nogueira da
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Palavras-chave em Português: Efeito quântico de Hall; Teoria da resposta linear; Sistemas quasi-bidimensionais; Semicondutores
• Link de acesso: http://www.repositorio.ufc.br/handle/riufc/12775

We investigate the effects of the spin-orbit interactions (both Rashba and Dresselhauss type), and a potential with one-dimensional periodic modulation on the physical properties of a non interacting bidimensional electron gas, in the presence of a tilted external d.c. magnetic field. The system is characterized by a set of parameters that determine the intensity and direction of the magnetic field, the intensities of the interactions Rashba and Dresselhaus, the intensity and periodicity of the potential and the number of particles for m2. Solutions of the equation of Schrödinger had been obtained for different sets of parameters, and this allowed us to calculate the density of states and the Fermi energy of the system, for each set of parameters. These results made possible the analysis of the conductivity, free energy, and magnetization in the direction of the field as a function of the inclination and the intensity of the external field and to analyze the relative importance of the Zeeman, spin-orbit interactions, and the onedimensional periodic potential on these properties. We observe modulation in the density of states due to the spin-orbit interactions. This behavior also is observed in the behavior of observables that depend on the dynamic variables of the system. Moreover, we also observe that the Hall conductivity is quantized in the absence of the periodic modulation, interaction spin-orbit and parallel field to the growth direction, and only assume multiple values of e2/h. In the presence of component the magnetic field parallel to the region where the gas is confined and/or spin-orbit interaction, there are intermediate plateaus (2n+1) e2/(2h) between any plateaus of order n and n+1. The presence of a periodic potential, makes possible the Hall conductivity have continuous values between two consecutive plateaus. Also we got that the periodic modulation makes the contribution the diffusivity to the conductivity have a finite value.