In a quantum ring connected with two external leads, the spin properties of an incoming electron are modified by the spin-orbit interaction, resulting in a transformation of the qubit state carried by the spin. The ring acts as a one-qubit spintronic quantum gate whose properties can be varied by tuning the Rashba parameter of the spin-orbit interaction, by changing the relative position of the junctions, as well as by the size of the ring. We show that a large class of unitary transformations can be attained with already one ring - or a few rings in series - including the important cases of the Z, X, and Hadamard gates. By choosing appropriate parameters the spin transformations can be made unitary, which corresponds to lossless gates.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - Jan 1 2005|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics