Tuning chiral edge state and spin-filtering in irradiated silicene nanoribbons based on side potentials

Topological edge states are critical for developing low-loss devices, making it essential to understand their properties. This study examines the influence of side potentials on the topological edge states in irradiated zigzag silicene nanoribbons. The potentials consist of three external fields, which collectively facilitate the emergence of modified chiral edge modes and spin-valley-related chiral edge states. The mechanism involves shifting the spin-polarized edge states outside the range of the Fermi level with the side potentials, thereby inducing intriguing topological edge states. Additionally, we propose a quasi-bulk state characterized by exponential decay that differs from conventional bulk modes. Based on these modified edge states, a tunable spin filter utilizing side potentials is proposed. We believe that these findings are essential for future developments in spintronic device design.