Zener quantum dot spin filter in a carbon nanotube
  We predict and analyze a novel spin filter in semiconducting carbon nanotubes. By using local electrostatic gates, the conduction and valence bands can be modulated to form a double-barrier structure. The confined region below the valence band defines a Zener quantum dot, which exhibits resonant tunneling. The resonances split in a magnetic field to make a bipolar spin filter for applications in spintronics and quantum information processing. We model this using k*p envelope function theory and show that this is in excellent agreement with a corresponding tight-binding calculation. 
D. Gunlycke, J.H. Jefferson, S.W.D. Bailey, C.J. Lambert, D.G.   Pettifor, G.A.D. Briggs