Quantum interference effects of the helical spin current are explored in two-dimensional topological insulators by means of a one-dimensional chain model that simulates the edge states. Peculiar transport properties of the circular edge are revealed in terms of an interferometer with two or three leads. The spin of transmitted electrons changes according to its kinetic energy and the arc lengths of the interferometer. It is also shown that the interferometer with three leads can generate spin polarized current from injection of spin unpolarized electrons.
- HGTE QUANTUM-WELLS