Identification of trivial and nontrivial insulators: Enhanced lateral shiftin topological insulator-based cavity

We theoretically exploit the parallel and perpendicular lateral shifts of topologicalinsulator slabby using stationary-phase approach. Compared with ordinary insulators, the perpendicularlateral shift of topological insulator exhibits unusual features, which provides a promisingapproach to differentiate these two phases. Furthermore, it is found that theperpendicular lateral shift of topological insulator is a surface-sensitive parameter and can be usedto extract its surface characteristics. Additionally, a topological insulator-basedcavity structure is proposed to remarkably enhance the lateral shift due to the localizeddefect mode, which enables better observation of the lateral shift in the experiment.