Magnetically Controlled Electronic Transport Properties of a Ferromagnetic Junction on the Surface of a Topological Insulator

We have investigated the transport properties of the Dirac fermions through a ferromagnetic barrier junction on the surface of a strong topologicM insulator. The current-voltage characteristic curve and the tunneling conductance are calculated theoretically. Two interesting transport features are predicted： observable negative differential conductances and linear conductances tunable from unit to nearly zero. These features can be magnetically manipulated simply by changing the spacial orientation of the magnetization. Our results may contribute to the development of high-speed switching and functional applications or electricalIy controlled magnetization switching.