Tunneling magnetoresistance and spin-valley polarization of aperiodic magnetic silicene superlattices

TL;DR

This study demonstrates that aperiodic magnetic silicene superlattices, especially Thue-Morse structures, enhance spin-valley polarization and tunneling magnetoresistance by reducing conductance oscillations compared to periodic superlattices.

Contribution

It introduces the use of aperiodic superlattices, specifically Fibonacci and Thue-Morse sequences, to improve spin-valley polarization and TMR in magnetic silicene superlattices.

Findings

Thue-Morse superlattices significantly reduce conductance oscillations.

Aperiodic superlattices achieve better spin-valley polarization and TMR.

Thue-Morse superlattices outperform Fibonacci and periodic structures.

Abstract

Magnetic silicene superlattices (MSSLs) are versatile structures with spin-valley polarization and tunneling magnetoresistance (TMR) capabilities. However, the oscillating transport properties related to the superlattice periodicity impede stable spin-valley polarization states reachable by reversing the magnetization direction. Here, we show that aperiodicity can be used to improve the spin-valley polarization and TMR by reducing the characteristic conductance oscillations of periodic MSSLs (P-MSSLs). Using the Landauer-B\"uttiker formalism and the transfer matrix method, we investigate the spin-valley polarization and the TMR of Fibonacci (F-) and Thue-Morse (TM-) MSSLs as typical aperiodic superlattices. Our findings indicate that aperiodic superlattices with higher disorder provide better spin-valley polarization and TMR values. In particular, TM-MSSLs reduce considerably the conductance oscillations giving rise to two well-defined spin-valley polarization states and a better TMR than F- and P-MSSLs. F-MSSLs also improve the spin-valley polarization and TMR, however they depend strongly on the parity of the superlattice generation.