Topological charge and spin pumping in a semiconductor nanowire

Abstract

The implementation of adiabatic topological pumping in a semiconductor nanowire is proposed by modulating the arranged gate potentials periodically. The topological charge pumping is demonstrated by simulating the Rice-Mele model on a periodic double-quantum-dot chain, and manifested by the gapless edge states in a finite chain with open boundary conditions. When exposed to an external staggered magnetic field, we show that the semiconductor nanowire can be used to implement the topological spin pumping and, meanwhile, serves as a dynamic version of the topological insulator in the presence of Rashba spin-orbit interaction. Explicitly, all the adiabatic pumps are confirmed by the nontrivial topological invariants of the Bloch functions under different modulations and, when the double-quantum-dot chain is coupled to the external leads, the topological transports can also be verified by exploiting the scattering matrix formulation.