Electromodulation of the magnetoresistance and spin-valley polarization in Fibonacci silicene superlattices by external electric fields

The transmittance, spin-valley polarization, and tunnelling magnetoresistance of a ferromagnetic silicene superlattice arranged in a Fibonacci sequence are explored using the transfer-matrix method and Landauer–Büttiker theory. Both parallel and antiparallel magnetization effects were studied for the lowest three Fibonacci orders (S₂,S₄,andS₆) as an external electric field was applied perpendicular to the silicene layer and the incident energy of Dirac electrons was modulated. In the S₂ configuration, the equivalence between the conductance of electrons in the K valley and electrons with opposite spin in the K^′ valley leads to zero polarizations in the antiparallel magnetization. However, the higher-order S₄andS₆ configurations present an aperiodic distribution of wells and barriers leading to non-zero polarizations. Additionally, we find that increasing the electric field intensity reduces conductance across all sequence configurations; however, increasing the incident energy increases conductance and splits some conductance components. We also discuss the dependence of the tunneling magnetoresistance on the electric field and incident electron energy for different configurations. Interestingly, our calculations predict a stable and perfect tunneling magnetoresistance for the S₆ configuration at lower incident energies.