1202.4874 (Awadhesh Narayan et al.)

Andreev reflection in two-dimensional topological insulators with either
conserved or broken time-reversal symmetry    [PDF]

Awadhesh Narayan, Stefano Sanvito

We investigate Andreev reflection in two-dimensional heterojunctions formed
by a superconductor in contact with a topological insulator ribbon either
possessing or breaking time-reversal symmetry. Both classes of topological
insulators exhibit perfect Andreev reflection, robust against disorder. This is
assigned to topologically protected edge states. In the time-reversal symmetric
case we show that doping one of the ribbon edges with magnetic impurities
suppresses one Andreev channel, while no such suppression is seen in the broken
symmetry situation. Based on this observation we suggest a transport experiment
able to distinguish between the two types of topological insulators.

View original: http://arxiv.org/abs/1202.4874