Quantum transport and absence of Anderson localization in strong and weak topological insulators
by
Jens Bardarson(University of California Berkeley)
→
Europe/Stockholm
122:026
122:026
Description
A single Dirac fermion, realized at the surface of a 3D strong
topological insulator, can not be localized by time reversal symmetric
disorder. Rather, the surface always flows into a symplectic metal
phase characterized by weak anti-localization. This absence of
Anderson localization in the surface is one of the characterizing
features of a topological insulator. The surface of a weak topological
insulator, however, does not have a topological protection against
Anderson localization yet, surprisingly, manages to avoid it under
general conditions. A metal-insulator transition is only obtained in
the presence of a time reversal symmetric mass. We demonstrate this,
and the resulting two parameter scaling, by a numerical solution of
the Dirac equation in the presence of Gaussian disorder. We briefly
discuss the role of a topological term in the underlying field theory
of diffusion and how it can be used, together with the demonstrated
absence of localization, to construct the perodic table of topological
insulators.
