Abstract
We study three-dimensional generalizations of the quantum spin Hall (QSH) effect. Unlike two dimensions, where a single topological invariant governs the effect, in three dimensions there are 4 invariants distinguishing 16 phases with two general classes: weak (WTI) and strong (STI) topological insulators. The WTI are like layered 2D QSH states, but are destroyed by disorder. The STI are robust and lead to novel “topological metal” surface states. We introduce a tight binding model which realizes the WTI and STI phases, and we discuss its relevance to real materials, including bismuth.
- Received 26 July 2006
DOI:https://doi.org/10.1103/PhysRevLett.98.106803
©2007 American Physical Society