Numerical Investigation of Shot Noise in Nanostructures including Chaotic Cavities and Potential Barriers

A numerical approach for the evaluation of conductance and shot noise suppression in mesoscopic structures is presented and applied to a few relevant cases. Details are provided both of the technique based on a recursive Green's function procedure that is used for calculations in the absence of a magnetic field and of the recursive scattering matrix method that is applied to simulations with nonzero magnetic field. Shot noise suppression in cascaded chaotic cavities is studied and discussed in comparison with the suppression obtained for cascaded potential barriers. It is observed that the Fano factor for multiple cascaded cavities is the same as that for a single cavity, as long as its apertures are small compared to its width. Finally, a particular structure, consisting in a cavity with a central potential barrier, is studied and from its noise behavior conclusions are drawn about the very different role played by a constriction or by a potential barrier in the presence of edge states.