Symmetries of quantum transport with Rashba spin-orbit: graphene spintronics

The lack of some spatial symmetries in planar devices with Rashba spin-orbit interactions opens up the possibility of producing spin polarized electrical currents in the absence of external magnetic fields or magnetic impurities. We study how the direction of the spin polarization of the current is related to spatial symmetries of the device. As an example of these relations we study numerically the spin-resolved current in graphene nanoribbons. Different configurations are explored and analyzed to demonstrate that graphene nanoflakes may be used as excellent spintronic devices in an all-electrical setup.This work was financially supported by CNPq and FAPERJ under grant E-26/101.522/2010 and by Spanish MINECO grant No. FIS2012-33521. We acknowledge the financial support from the CNPq/CSIC project 2011BR0087 and the INCT de Nanomateriais de carbono