Surface states in negative-band-gap semiconductor films: Intrinsic or topological?

We show that in HgTe films with passivated surface, surface states evolve from the cation derived dangling-back bond band and that they must be classified as intrinsic surface states of the inverted gap materials. The surface states can only be formed when the passivating potential reaches a threshold value needed to overlap the positive band gap of the surface layers and negative band gap of the interior layers of the slabs. The surface states found do not have characteristic topological properties. Depending on a terminating layer, these surface states are gapless or quasi-gapless at the zone center, but they cannot prevent back-scattering.