Topological spin and valley pumping in silicene.

Wei Luo,B G Wang,L Sheng,D Y Xing

doi:10.1038/srep31325

Abstract

We propose to realize adiabatic topological spin and valley pumping by using silicene, subject to the modulation of an in-plane ac electric field with amplitude Ey and a vertical electric field consisting of an electrostatic component and an ac component with amplitudes and . By tuning and , topological valley pumping or spin-valley pumping can be achieved. The low-noise valley and spin currents generated can be useful in valleytronic and spintronic applications. Our work also demonstrates that bulk topological spin or valley pumping is a general characteristic effect of two-dimensional topological insulators, irrelevant to the edge state physics.

Highlights

We propose to realize adiabatic topological spin and valley pumping by using silicene, subject to the modulation of an in-plane ac electric field with amplitude Ey and a vertical electric field consisting of an electrostatic component and an ac component with amplitudes Ez0 and Ez1
Our work demonstrates that bulk topological spin or valley pumping is a general characteristic effect of twodimensional topological insulators, irrelevant to the edge state physics
We have investigated the topological pumping effect in silicene, modulated by an in-plane and a vertical time-dependent electric field

Summary

OPEN Topological spin and valley pumping in silicene

Chen et al proposed that a spin Chern pumping effect from the bulk of the 2D TI, a HgTe quantum well, can be realized by using time-dependent dual gate voltages and an in-plane ac electric field[17], which paves a way for direct investigation and utilization of the bulk topological properties of the TIs. The work of Chen et al is a generalization of the earlier proposals of topological spin pumps[18,19,20,21,22], based upon 1D abstract models, to a realistic 2D TI material. It is proportional to the cross-section of the sample, and insensitive to the material parameters, a clear evidence that the pumping is a bulk topological effect, irrelevant to the edge states

Results

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Conclusion

Additional Information