Band-inversion interface Dirac states were first modeled by B. A. Volkov and O. A. Pankratov in 1985, and the 2D ℤ₂ topological invariant protected by time-reversal symmetry was formulated by Charles Kane and Eugene Mele in 2005.
2D quantum spin Hall edge transport was first realized experimentally in HgTe/CdTe quantum wells by Laurens Molenkamp's group in 2007, followed by 3D topological surface states in Bi_(1−x)Sb_x, Bi₂Se₃, and Bi₂Te₃.
Because surface Dirac electrons have their spin locked perpendicular to their momentum, backscattering from non-magnetic impurities is suppressed.