Electrical tuning of spin current in a boron nitride nanotube quantum dot

Controlling spin current and magnetic exchange coupling by applying an electric field and achieving high spin injection efficiency at the same time in a nanostructure coupled to ferromagnetic electrodes have been the outstanding challenges in nanoscale spintronics. A relentless quest is going on to find new low dimensional materials with tunable spin dependent properties to address these challenges. Herein, we predict, from first principles, the transverse electric field induced switching in the sign of exchange coupling and tunnel magnetoresistance in a boron nitride nanotube quantum dot attached to ferromagnetic nickel contacts.