Improvement of the spin-valley polarization and tunneling magnetoresistance in magnetic silicene superlattices by means of aperiodic Kolakoski order

Abstract

Aperiodic order is quite relevant in science and technology. The aperiodic order is characterized by the so-called aperiodic sequences. Among the most important sequences we can find the Fibonacci, Thue–Morse, and Cantor sequences. The Thue–Morse and Cantor sequence have been instrumental in improving the spin-valley polarization and tunneling magnetoresistance (TMR) of magnetic silicene superlattices (MSSLs). Here, we study the impact of aperiodic Kolakoski order on the spin-valley polarization and TMR of MSSLs. The spin-valley polarization and TMR of Kolakoski (K-) MSSLs are compared with the ones of periodic (P-), Thue–Morse (TM-), and Cantor (C-) MSSLs. We find that the higher degree of disorder of the Kolakoski sequence reduces the total conductance of the antiparallel magnetization configuration, resulting in an effective enhancement of the TMR. Also, the aperiodic Kolakoski order gives rise to energy regions of two well-defined spin-valley polarization states accessible by switching the magnetization direction. The aperiodic Kolakoski order in conjunction with structural asymmetry can optimize the spin-valley polarization and TMR of MSSLs. The spin-valley polarization and TMR capabilities of K-MSSLs are superior than the ones of P-, TM-, and C-MSSLs.