| Electrical manipulation of conduction band electron spins in nonmagnetic semiconductors is achieved by exploiting various manifestations of the spin-orbit interaction. The effective Lande g-factor in semiconductor crystals, which differs by a significant amount from the free-electron g-factor, is engineered by using materials with different band parameters. Such g-factor engineering combined with bandgap engineering leads to electrical tuning of the g-factor by changing the position of the electron wave function within parabolic quantum wells. Anisotropy of the g-tensor in these structures enables an implementation of g-tensor modulation resonance through electrical control of the g-tensor. In a complementary approach, the momentum-dependent spin splitting in the conduction band manipulates spins. The strain-induced spin splitting is used to demonstrate coherent rotation of spins, even in zero magnetic field. The effective internal magnetic fields were also used to electrically polarize electron spins. Observation of the spin Hall effect is also reported, which refers to the generation of a pure spin current transverse to an applied electric field even it the absence of applied magnetic fields. |
