Semiconductor pumps modulated by planar external fields

Semiconductor pumps modulated by external fields in the spin-momentum plane are investigated in this work. The central pump comes from the driving of the double time-dependent delta potentials, which are formed in interfaces of the Dresselhaus spin-orbit coupling (SOC) region attached to two normal leads. Floquet scattering matrix method calculations show that charge currents pumped from the system can be strengthened by modulations of the planar external fields besides the potentials and SOCs. Even in fixed parametric semiconductor pumps, enhanced pure spin currents can be achieved with some strength and direction coeffects of the planar external fields.