In "Topological Insulators and Topological Superconductors" by Bernevig and Taylor, it is written on page 60:
In a seminal paper, Laughlin argued that the presence of edge modes is an inescapable consequence of transverse quantized transport in an insulator. This is even more remarkable because at that time it was widely accepted that delocalized states cannot exist in two dimensions, whereas Laughlin’s argument says that delocalized states must exist.
Similarly, in the top answer to Why are Bloch waves so successful at explaining behaviour of electrons in crystals?, it is mentioned:
In two dimensions, any amount of disorder will destroy the extended Bloch wave eigenstates, but in three dimensions, there is a threshold below which fluctuations and disorder do not change the Bloch structure too much
But we routinely solve for graphene's Bloch states, and so many experiments are done with graphene conduction, which would verify the presence of delocalized states.
How can infinitesimal disorder in 2D destroy all delocalized states and how 2D materials still have IV characteristics that are described using Bloch states while actually there is absence of delocalized states?
