1207.2480 (Hermann Schulz-Baldes)

Persistence of spin edge currents in disordered quantum spin Hall
systems    [PDF]

Hermann Schulz-Baldes

For a disordered two-dimensional model of a topological insulator (such as a Kane-Mele model with disordered potential) with small coupling of spin invariance breaking term (such as the Rashba coupling), it is proved that the spin edge currents persist provided there is a spectral gap and the spin Chern numbers are well-defined and non-trivial. These conditions on being in the quantum spin Hall phase do not require time-reversal symmetry. The result materializes the general philosophy that topological insulators are non-trivial bulk systems with edge currents that are topologically protected against Anderson localization.

View original: http://arxiv.org/abs/1207.2480