Magnetic-Field-Induced Charge Transport In Quantum Wires With Spin-Orbit Coupling

The spin-related phenomena in semiconductor nanostructures are currently attracting considerable interest, and it is a great important research aspect in semiconductor spin electronics. The spin current injects semiconductor from ferromagnetic electrode and produces cumulation in interface and inside semiconductor. It is a major problem how to modulate and control spin polarized current, especially in spin-orbit coupled systems. In these systems, we can utilize spin-orbit interaction, and modulate its exterior parameter to control electronic spin polarized transport or charge transport. Especially the Rashba spin-orbit interactions play an important role in controlling and manipulating the spin and charge degrees of freedom in low-dimensional systems. As a result, in the recent years the attention has been drawn to the spin-related behavior of quasi-one-dimensional electron systems (two-dimensional electronic system confined by a potential along the x direction, the electrons can only movement along the y direction) in the presence of the Rashba spin-orbit coupling (Rashba spin-orbit coupling produced by confined potential in bound surface with structure inversion asymmetry). Recently there are a lot of works to describe electron behavior of quasi-one-dimensional in the presence of Rashba spin-orbit coupling in detail, and get some good results.In this thesis, we focus on the charge response in a quasi-one-dimensional electron quantum wire in the presence of Rashba spin-orbit coupling and electron-impurity scattering subject to an time-dependent applied magnetic field. By using the density matrix method and quantum transport equation, we have shown that the time-dependent magnetic field can induce a finite electrical current in the absence of any electric field when the mixing of subband is taken into account. This zero-electric-field current is due to the photo-excited electrons scattered by impurities in the presence of spin-orbit coupling. Our result provides an alternative method to produce and manipulate charge current by using a magnetic field alone in semiconductor spintronic systems.