Orbital Mechanisms of Electron-Spin Manipulation by an Electric Field

A theory of spin manipulation of quasi-two-dimensional (2D) electrons by a time-dependent gate voltage applied to a quantum well is developed. The Dresselhaus and Rashba spin-orbit coupling mechanisms are shown to be rather efficient for this purpose. The spin response to a perpendicular-to-plane electric field is due to a deviation from the strict 2D limit and is controlled by the ratios of the spin, cyclotron, and confinement frequencies. The dependence of this response on the magnetic field direction is indicative of the strengths of the competing spin-orbit coupling mechanisms.

Figure 1

Angular dependence of the EDSR intensity $I(\theta ,\phi )$ for a $(0,0,1)$ QW (in arbitrary units) calculated for (a) Rashba SIA and (b) Dresselhaus BIA mechanisms. Parameter values ${\omega }_s/{\omega }_c=-0.17$ (as in InAs) and ${\omega }_c/{\omega }_0=0.5$ (as in Ref. 4) were used. To cut off the pole in $I(\theta ,\phi )$ at ${\omega }_{\xi }^2(\theta )={\omega }_s^2$, an imaginary part $i\Gamma$ with $\Gamma =0.08{\omega }_c$ was added to ${\omega }_c$.