Strong side of weak topological insulators

Zohar Ringel*, Yaacov E. Kraus, Ady Stern

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

166 Scopus citations


Three-dimensional topological insulators are classified into "strong" (STI) and "weak" (WTI) according to the nature of their surface states. While the surface states of the STI are topologically protected from localization, this does not hold for the WTI. In this work, we show that the surface states of the WTI are actually protected from any random perturbation that does not break time-reversal symmetry, and does not close the bulk energy gap. Consequently, the conductivity of metallic surfaces in the clean system remains finite even in the presence of strong disorder of this type. In the weak disorder limit, the surfaces are found to be perfect metals, and strong surface disorder only acts to push the metallic surfaces inwards. We find that the WTI differs from the STI primarily in its anisotropy, and that the anisotropy is not a sign of its weakness but rather of its richness.

Original languageAmerican English
Article number045102
JournalPhysical Review B - Condensed Matter and Materials Physics
Issue number4
StatePublished - 2 Jul 2012
Externally publishedYes


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