[13p-PA1-1~33] 10 Spintronics and Magnetics（Poster）

[13p-PA1-5] Spin Filtering in Aharonov-Bohm Ring with Double Quantum Dots under General Rashba Spin Orbit Interactions

〇Kenji Kondo¹ (1.Hokudai Univ, RIES.)

Keywords:Rashba Spin Orbit Interaction,Spin Filter,Aharonov-Bohm Ring

Many researchers have reported about the spin-filters using linear Rashba SOI. However, the spin-filters using square and cubic Rashba SOIs are not yet reported. We consider that this is because that the AC phases acquired under square and cubic Rashba SOIs are ambiguous. In this study, we try to derive the AC phases acquired under square and cubic Rashba SOIs from the viewpoint of non-Abelian SU (2) gauge theory. These AC phases can be derived successfully from the non-Abelian SU (2) gauge theory without the completing square methods. Using the results, we investigate the spin filtering in double quantum dots Aharonov-Bohm (AB) ring under linear, square, and cubic Rashba SOIs. This AB ring consists of elongated quantum dots and quasi-one dimensional quantum nanowires under external magnetic field. The spin transport is investigated from left nanowire to right nanowire in the above structure within tight binding approximation. In particular, we focus on the difference of spin filtering among linear, square, and cubic Rashba SOI. The calculation is performed for the spin polarization with changing the penetrating magnetic flux for the AB ring subject to linear, square, and cubic Rashba SOI, respectively. It is found that the perfect spin filtering is achieved for all the Rashba SOIs. This result indicates that this AB ring under general Rashba SOIs can be a promising device for spin current generation. Moreover, they behave in totally different ways in response to penetrating magnetic flux, which is attributed to linear, square, and cubic behaviors in the in-plane momentum. This result enables us to make a clear distinction among linear, square and cubic Rashba SOIs according to the peak position of the perfect spin filtering.