Nanojunctions as logic operators for the spintronics
INFN, Laboratori Nazionali di Frascati, P.O. Box 13, 00044 Frascati, Italy
2 Department of Physics "A. Volta", University of Pavia, via Bassi 6, 27100 Pavia, Italy
Corresponding author: firstname.lastname@example.org
Revised: 12 November 2009
Published online: 21 January 2010
We propose two all-electrical nanodevices where the spin properties of an incoming electron are modified by the spin-orbit interaction (SOI), resulting in a transformation of the qubit state carried by the spin. Our proposal is essentially based on nanojunctions made of crossing quantum wires patterned in a two dimensional electron gas where the Rashba SOI is present. We investigate in detail the spin precession of one electron traveling in the proposed nanodevices. The nanojunctions acts as spin filters or ballistic spin rotators whose properties can be varied by tuning the strength of the SOI, by changing the geometry of the junctions. Two different basic mechanism in order to obtain in plane or out of the plane rotations are discussed. We show that, starting from the spin rotators, a large class of unitary transformations can be attained with one or more nanojunctions in series. By choosing appropriate parameters the spin transformations can be made unitary, which corresponds to lossless operators.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2010