Ballistic electron transmission through interfaces.

We report on a new method for calculating ballistic electron transmission through epitaxial interfaces and its application to a silicon twist boundary. This method is based on constructing the electronic states of the infinite system from the generalized Bloch states for each layer in the structure; these states are matched together at the layer boundaries to construct the composite wavefunction. We find that the conduction band electrons and heavy holes within thermal energies of the band gap are strongly scattered by the twist boundary, but that the light holes in the same energy range are not. These results, which are unexpected from naive effective mass considerations, can be simply understood in terms of flux patterns of the band extrema wavefunctions on the interface matching plane.