Topological Spin and Valley Pumping in Silicene

TL;DR

This paper proposes a method to realize adiabatic topological spin and valley pumping in silicene using electric fields, producing noisefree currents relevant for valleytronics and spintronics.

Contribution

It introduces an experimental scheme for topological spin and valley pumping in silicene, independent of edge states, expanding the understanding of bulk topological effects.

Findings

Achieved tunable topological valley and spin-valley pumping.

Generated noisefree spin and valley currents.

Demonstrated bulk topological pumping as a general effect in 2D topological insulators.

Abstract

We propose an experimental scheme to realize adiabatic topological spin and valley pumping by using silicene subject to an in-plane $ac$ electric field with amplitude $E_{y}$ and a vertical electric field consisting of an electrostatic component and an $ac$ component with amplitudes $E_{z}^{0}$ and $E_{z}^{1}$. By tuning $E_{z}^{0}$ and $E_{z}^{1}$, topological valley pumping or spin-valley pumping can be achieved. The noisefree valley and spin currents generated could be useful in valleytronic and spintronic applications. This work demonstrates that bulk topological spin or valley pumping is a general characteristic effect of two-dimensional topological insulators, irrelevant to the edge state physics.