Backscattering in a 2D topological insulator and conductivity of a 2D strip
L. I. Magarill, M. V. Entin
Rzhanov Institute of Semiconductor Physics SB of the RAS, 630090 Novosibirsk, Russia
Novosibirsk State University, 630090 Novosibirsk, Russia
Abstract
A strip of the 2D HgTe topological insulator is studied.
The
same-spin edge states in an ideal system propagate in opposite directions on
different sides of the strip and do not mix by tunneling. Impurities, edge
irregularities, and phonons produce transitions between the contra-
propagating edge states on different edges. This backscattering determines
the conductivity of an infinitely long strip. The conductivity at finite
temperature is determined in the framework of the kinetic equation. It is
found that the conductivity exponentially grows with the strip width. In the
same approximation the non-local resistance coefficients of a 4-terminal
strip are found.