Transporte eletrônico em sistemas de baixa dimensionalidade

Abstract

The electronic transport phenomena are of fundamental importance in understanding the basic properties of matter. They also play essentials part on the development of new technological applications. Electronic transport is average movement of a large amount of electrons in one given direction, forming what is identified macroscopically as an electric chain. All computational devices in operation today use electronic transport to store and process information. In this work we studied electronic transport in system of low dimensionality and described through simple models. The reduced number of space dimensions makes the mathematics of the models, simpler than those of three-dimensional systems. The systems were modeled by sequences of quantum barriers, that is, relatively abrupt space variations of the potential energy. That kind of system has been studied intensely in last the two decades due to the peculiar properties originating from the electronic confinement. Also important is the fact that the new technologies of materials production have been allowing the fabrication of system of even more dimensions. The electronic transport in these models has been analyzed through the calculation of the transmission coefficient. The behavior of the transmission coefficient as function of energy shows signatures of quantum interferences, tunneling and formation of discrete levels of energy.