Termogravimetria de cascas de arroz.

bitstream/CNPDIA-2009-09/11065/1/CT89_2007.pd

Numerical analysis of the resistance behavior of an electrostatically-induced graphene double junction

We present a numerical approach that we have developed in order to reproduce and explain the resistance behavior recently observed, as a function of the backgate voltage and of the position of a biased scanning probe, in a graphene flake in which a double p-n junction has been electrostatically induced. A simplified electrostatic model has been adopted to simulate the effect of gate voltages on the potential landscape, assuming for it a slow variation in space and using a simple capacitive model for the coupling between the electrodes and the graphene sheet. The transport analysis has then been performed with a solution of the Dirac equation in the reciprocal space coupled with a recursive scattering matrix approach. The efficiency of the adopted numerical procedure has allowed us to explore a wide range of possible potential landscapes and bias points, with the result of achieving a good agreement with available experimental data

Analysis of shot noise suppression in mesoscopic cavities in a magnetic field

We present a numerical investigation of shot noise suppression in mesoscopic cavities and an intuitive semiclassical explanation of the behavior observed in the presence of an orthogonal magnetic field. In particular, we conclude that the decrease of shot noise for increasing magnetic field is the result of the interplay between the diameter of classical cyclotron orbits and the width of the apertures defining the cavity. Good agreement with published experimental results is obtained, without the need of introducing fitting parameters.Comment: 5 pages, 3 figures, contents changed (final version