# Nonlocal Transport in the Quantum Spin Hall State

It has been reported that nonlocal Transport in the can be realized in topological insulator. Why non-local transport through edge channels has the potential application for low-power information processing?

-
I think the most knowledgeable person on this matter on stackexchange is Prof. Liang Fu. He's the best person to ask! I think the reason you can have low-power applications is that these edge channels have a conductance of $2e^2/h$ despite varying levels of disorder. In other words, these channels are robust to disorder. – NanoPhys Oct 22 '12 at 16:41

The short answer is that in topological insulators, spin-orbit coupling allows for the creation of a [topological] class of insulating bands where time reversal symmetry is unbroken with topologically protected edge states at the boundaries of the sample. These edge states are similar in spirit to those which arise in the integer quantum Hall effect but in absence of magnetic field. The spatially separated edge channels are also helical or spin-filtered and robust against weak electron-electron interactions and disorder. This is why, if we are able to coherently control transport in these systems, we could think of different applications for spintronic or magnetospintronic devices (the dream is usually the Datta-Das spin-FET).

For further information, I would recommend you, in case you don't know, the excellent review of Hasan and Kane http://arxiv.org/abs/1002.3895

-