PythTB is a software package providing a Python implementation of the
tight-binding approximation. It can be used to construct and solve
tight-binding models of the electronic structure of systems of
arbitrary dimensionality (crystals, slabs, ribbons, clusters, etc.),
and is rich with features for computing Berry phases and related
properties. For more details, please see:

   http://www.physics.rutgers.edu/pythtb/