Revisiting the nature of topological insulator transitions in three dimensions in the presence of disorder

The phase diagram of a three-dimensional ℤ₂ topological insulator in the presence of short-ranged potential disorder is reconsidered due to the improved understanding of non-perturbative rare states that destabilize the noninteracting Dirac semimetal critical point that separates different topological phases. Using the kernel polynomial method on GPUs we compute transport properties on large system sizes, which we combine with a study of the wavefunctions obtained via Lanczos. Based on this data we argue that expected Dirac semimetal line is destabilized into a diffusive metal phase of finite extent due to non-perturbative effects of rare regions.