Photon-assisted spin transport characteristics of A-B interferometer embedded with three quantum dots

We design an A-B interferometer with a “single quantum dot atom” embedded in the upper arm and a “double quantum dot molecule” embedded in the lower arm. The transmission coefficient and average current characteristics are studied as the time-dependent external field is introduced. When the interdot coupling strength is weak, the change of Rashba spin orbit coupling strength has a strong influence on the spin transmission coefficient. When the interdot coupling strength and Rashba spin orbit coupling strength take appropriate values, the spin up and spin down transmission coefficients completely coincide, and a resonance band emerges at the Fermi level. The spin polarization can be close to +1 or −1 by adjusting the Zeeman magnetic field, the interdot coupling strength, and the gate voltage. In the presence of photon assistance, the spin polarization changes periodically in a certain proportion, so as to realize the spin-polarized transport with controllable time-dependent external field. These findings provide a theoretical basis for the spin polarized function of A-B interferometer. •The spin transmission coefficient produces Fano effect at the Fermi level.•The system can be used as a spin filter by adjusting the Zeeman magnetic field and the gate voltage.•When the time-dependent external field is introduced, the spin polarization changes quasi periodically.•The system can be used to realize the electrical components of spin current polarization transport unit.