1202.3187 (Chushun Tian)

Superdiffusion in the topological metal    [PDF]

Chushun Tian

We develop a non-perturbative theory to study large-scale quantum dynamics of
Dirac particles in disordered scalar potentials (the so-called "topological
metal"). For general disorder strength and carrier doping, we find that at
large times, superdiffusion occurs. I.e., the mean squared displacement grows
as $\sim t\ln t$. In the static limit, our analytical theory shows that the
conductance of a finite-size system obeys the scaling equation identical to
that found in previous numerical studies. These results suggest that in the
topological metal, there exist some transparent channels -- where waves
propagate "freely" -- dominating long-time transport of the system. We discuss
the ensuing consequence -- the transverse superdiffusion in photonic materials
-- that might be within the current experimental reach.

View original: http://arxiv.org/abs/1202.3187