  The adiabatic topological pumping is proposed by periodically modulating a
semiconductor nanowire double-quantum-dot chain. We demonstrate that the
quantized charge transport can be achieved by a nontrivial modulation of the
quantum-dot well and barrier potentials. When the quantum-dot well potential is
replaced by a time-dependent staggered magnetic field, the topological spin
pumping can be realized by periodically modulating the barrier potentials and
magnetic field. We also demonstrate that in the presence of Rashba spin-orbit
interaction, the double-quantum-dot chain can be used to implement the
topological spin pumping. However, the pumped spin in this case can have a
quantization axis other than the applied magnetic field direction. Moreover, we
show that all the adiabatic topological pumping are manifested by the presence
of gapless edge states traversing the band gap as a function of time.
