  The bandstructures of [110] and [001] Bi2Te3 nanowires are solved with the
atomistic 20 band tight binding functionality of NEMO5. The theoretical results
reveal: The popular assumption that all topological insulator wire surfaces are
equivalent is inappropriate. The Fermi velocity of chemically distinct wire
surfaces differs significantly which creates an effective in-surface
confinement potential. As a result, topological insulator surface states prefer
specific surfaces. Therefore, experiments have to be designed carefully not to
probe surfaces unfavorable to the surface states (low density of states) and
thereby be insensitive to the TI-effects.
