A computer code for lattice Weyl-Wigner simulations of transport in circular cylindrical nanostructures

We have constructed a code that generalizes the Buot-Jensen algorithm to the calculation of electron transport in two-dimensional circular-cylindrically symmetric structures. The code differs significantly from the one-dimensional version in two aspects. First, the code is to be run on a Beowulf-class cluster to obtain the benefits of parallelization, but data movement between processors is of concern. The processors each handle one or more radial slices, hence the exchange of the Wigner function data is needed for a straightforward calculation of radial drift. We are presently evaluating the exchange of a limited number of moments of the Wigner distribution and its subsequent approximate reconstruction. The approximations employed in the calculation of the four-dimensional convolution integral of the Wigner function and the potential will be exhibited. Even with the rough approximations we presently use, this portion is computationally the most expensive, so that improvements, while desirable, are a challenge to implement efficiently.