Tuning and detection of spin change in the conductance of confined systems using the Fano–Rashba effect

In general, resonant tunneling peaks do not show spin change fingerprints in the conductance, which makes detectable manipulation of spin change difficult. Here we show that by changing the spatial region where the Rashba effect is applied, on the input and output sides of an open quantum dot (OQD), we can determine the spin change at the resonant tunneling peaks, this does not happen when only the intensity of the Rashba parameter is changed. The determination of the spin change is associated with an inversion of the neighboring asymmetric Fano resonance, induced by the localized Rashba effect on the sides of the OQD (Fano–Rashba effect), which can be directly observed in the conductance. We also show here that localized antidots for specific positions within of OQD control and tune spin-polarized tunneling peaks, individually and selectively. With this, we show how to generate and manipulated asymmetric Fano resonances (associated with the states of the OQD itself), for the spin-flipping detections directly in the conductance, which is important for spintronics applications, without the use of a magnetic field. Here we find, that the soft-wall confinement of OQD defines much better the tuning and manipulation of Fano resonances, in relation to the parabolic confinement, which can be used for applications in spin filters due to its greater robustness against imperfections. Our results can be tested using AFM tips in OQDs, and the effects studied can be observed in systems based on heterostructures.