Topologically Protected AC Transport Induced by Spin–Orbit Interaction in H-Shaped Silicene Nanojunction

The linear ac transport properties are theoretically studied in H-shaped zigzag silicene nanojunction. We numerically calculated the dc conductance and ac emittance by considering the nearest-neighbor hopping, the second-nearest-neighbor spin-orbit interaction (SOI), and external electric field, based on the tight-binding approach and the ac transport theory. It is found that the relatively large SOI induces a topological quantum edge state in the nanojunction, which eliminates the ac emittance response at the Dirac point. Further investigations indicate that the SOI-induced ac transport is topologically protected, despite the changes of geometric size. Moreover, the external electric field would open an energy gap, and destroy the topological quantum state, making the nanojunction a trivial band insulator.