Momentum and spin filtering of electrons on the surface of a topological insulator

We study theoretically electron tunneling through planar magnetic barrier arrays on the surface of a three-dimensional topological insulator. Interestingly, the transmission displays a collimation behavior at some specific incident angles. This feature provides us a new way to construct a momentum and spin filter in topological insulators.

► The transmission is asymmetric with respect to the in-plane momentum kyky along the interface.
► The transmission displays a collimation behavior at some specific incident angles.
► Utilizing planar magnetic barrier arrays on the surface of a 3D TI to realize momentum and spin filter.