Manipulating spin dynamics in one-dimension using transverse magnetic focusing.

Transport in one-dimensional (1D) nanostructures in particular the impact of exchange-correlation terms on the spin dynamics has become an increasingly important area of research. In this regard, using transverse magnetic focusing (TMF), we may explore the spatial separation of spins as a function of splitting of periodic focusing peaks [1]. This separation is highly dependent on a difference in k_F of the spin-states and becomes tuneable with charge carrier density and out of plane asymmetry due to spin orbit coupling [2]. In the present work we aim to leverage high quality GaAs/AlGaAs heterostructures to define longer, and wider 1D quantum wires to form injector and detector in the TMF configuration. However, the relatively weaker spin orbit coupling in this system, compared to others with reported peak splitting [2], requires new measures for inducing different k_F of the spin-states, which may result in of improvement in peak splitting. Recently we achieved this by incorporating a top-gate over the focusing path. This top gate induced splitting in peaks was found to vary with the application of in-plane magnetic field, suggesting the effect is spin related. Results will be discussed with reference to existing theories around spin orbit coupling, exchange interactions as well as the device geometries.

[1] C Yan et al, J. Phys.: Condens. Matter 30, 08LT01 (2018)

[2] ST. Lo et al, Nat. Comm. 8, 15997 (2017)