Three-dimensional network model for strong topological insulator transitions

We construct a three-dimensional (3D), time-reversal symmetric generalization of the Chalker-Coddington network model for integer quantum Hall transition. In addition to weak topological insulator phase already accommodated by framework in preexisting literature, our hosts strong phases. unambiguously demonstrate that phases emerge as intermediate between trivial and phase. Additionally, we found duality relates model. Remarkably, are mapped themselves under this duality. show upon adding sufficiently disorder, undergo transitions into metallic numerically determine critical exponent insulator-metal Our explicitly shows how semiclassical percolation picture two dimensions can be generalized 3D opens up venue studying transitions.